diff --git a/BUILD b/BUILD
index c3f5a11..3b896ff 100644
--- a/BUILD
+++ b/BUILD
@@ -25,6 +25,7 @@
 junit_tests(
     name = "high-availability_tests",
     srcs = glob(["src/test/java/**/*.java"]),
+    javacopts = ["-Xep:DoNotMock:OFF"],
     resources = glob(["src/test/resources/**/*"]),
     tags = [
         "high-availability",
diff --git a/WORKSPACE b/WORKSPACE
index 6969594..acca707 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -3,7 +3,7 @@
 load("//:bazlets.bzl", "load_bazlets")
 
 load_bazlets(
-    commit = "87fd5f0d0a89d01df13deaf2d21a4bdb3bc03cfd",
+    commit = "8dc0767541f16b35d2136eccebffd9ebe2b81133",
     #local_path = "/home/<user>/projects/bazlets",
 )
 
diff --git a/src/main/java/com/ericsson/gerrit/plugins/highavailability/Configuration.java b/src/main/java/com/ericsson/gerrit/plugins/highavailability/Configuration.java
index 093628e..af1c4c3 100644
--- a/src/main/java/com/ericsson/gerrit/plugins/highavailability/Configuration.java
+++ b/src/main/java/com/ericsson/gerrit/plugins/highavailability/Configuration.java
@@ -17,6 +17,7 @@
 import static java.util.concurrent.TimeUnit.HOURS;
 import static java.util.concurrent.TimeUnit.MILLISECONDS;
 
+import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.CharMatcher;
 import com.google.common.base.Strings;
 import com.google.common.collect.ImmutableList;
@@ -77,8 +78,9 @@
     STATIC
   }
 
+  @VisibleForTesting
   @Inject
-  Configuration(
+  public Configuration(
       PluginConfigFactory pluginConfigFactory, @PluginName String pluginName, SitePaths site) {
     Config cfg = pluginConfigFactory.getGlobalPluginConfig(pluginName);
     main = new Main(site, cfg);
diff --git a/src/main/java/com/ericsson/gerrit/plugins/highavailability/autoreindex/IndexTs.java b/src/main/java/com/ericsson/gerrit/plugins/highavailability/autoreindex/IndexTs.java
index 561bb19..62d9c10 100644
--- a/src/main/java/com/ericsson/gerrit/plugins/highavailability/autoreindex/IndexTs.java
+++ b/src/main/java/com/ericsson/gerrit/plugins/highavailability/autoreindex/IndexTs.java
@@ -133,12 +133,12 @@
     currCtx.onlyWithContext(
         (ctx) -> {
           try {
-            ChangeNotes changeNotes = changeFinder.findOne(projectName + "~" + id);
+            Optional<ChangeNotes> changeNotes = changeFinder.findOne(projectName + "~" + id);
             update(
                 IndexName.CHANGE,
-                changeNotes == null
+                !changeNotes.isPresent()
                     ? LocalDateTime.now()
-                    : changeNotes.getChange().getLastUpdatedOn().toLocalDateTime());
+                    : changeNotes.get().getChange().getLastUpdatedOn().toLocalDateTime());
           } catch (Exception e) {
             log.atWarning().withCause(e).log("Unable to update the latest TS for change %d", id);
           }
diff --git a/src/main/java/com/ericsson/gerrit/plugins/highavailability/cache/CachePatternMatcher.java b/src/main/java/com/ericsson/gerrit/plugins/highavailability/cache/CachePatternMatcher.java
index 0f43eaf..baf512f 100644
--- a/src/main/java/com/ericsson/gerrit/plugins/highavailability/cache/CachePatternMatcher.java
+++ b/src/main/java/com/ericsson/gerrit/plugins/highavailability/cache/CachePatternMatcher.java
@@ -26,7 +26,7 @@
 @Singleton
 class CachePatternMatcher {
   private static final List<String> DEFAULT_PATTERNS =
-      ImmutableList.of("accounts", "^groups.*", "ldap_usernames", "projects", "sshkeys");
+      ImmutableList.of("^groups.*", "ldap_usernames", "projects", "sshkeys");
 
   private final Pattern pattern;
 
diff --git a/src/main/java/com/ericsson/gerrit/plugins/highavailability/forwarder/ForwardedAwareEventBroker.java b/src/main/java/com/ericsson/gerrit/plugins/highavailability/forwarder/ForwardedAwareEventBroker.java
index f156da4..fb651b7 100644
--- a/src/main/java/com/ericsson/gerrit/plugins/highavailability/forwarder/ForwardedAwareEventBroker.java
+++ b/src/main/java/com/ericsson/gerrit/plugins/highavailability/forwarder/ForwardedAwareEventBroker.java
@@ -14,6 +14,7 @@
 
 package com.ericsson.gerrit.plugins.highavailability.forwarder;
 
+import com.google.gerrit.server.config.GerritInstanceId;
 import com.google.gerrit.server.events.Event;
 import com.google.gerrit.server.events.EventBroker;
 import com.google.gerrit.server.events.EventListener;
@@ -23,6 +24,8 @@
 import com.google.gerrit.server.plugincontext.PluginSetContext;
 import com.google.gerrit.server.project.ProjectCache;
 import com.google.inject.Inject;
+import java.util.Objects;
+import javax.annotation.Nullable;
 
 class ForwardedAwareEventBroker extends EventBroker {
 
@@ -32,12 +35,30 @@
       PluginSetContext<EventListener> unrestrictedListeners,
       PermissionBackend permissionBackend,
       ProjectCache projectCache,
-      Factory notesFactory) {
-    super(listeners, unrestrictedListeners, permissionBackend, projectCache, notesFactory);
+      Factory notesFactory,
+      @Nullable @GerritInstanceId String gerritInstanceId) {
+    super(
+        listeners,
+        unrestrictedListeners,
+        permissionBackend,
+        projectCache,
+        notesFactory,
+        gerritInstanceId);
+  }
+
+  private boolean isProducedByLocalInstance(Event event) {
+    return Objects.equals(event.instanceId, gerritInstanceId);
   }
 
   @Override
   protected void fireEventForUnrestrictedListeners(Event event) {
+    // An event should not be dispatched when it is "forwarded".
+    // Meaning, it was either produced somewhere else
+    if (!isProducedByLocalInstance(event)) {
+      Context.setForwardedEvent(true);
+    }
+    // or it was consumed by the high-availability rest endpoint and
+    // thus the context of its consumption has already been set to "forwarded".
     if (!Context.isForwardedEvent()) {
       super.fireEventForUnrestrictedListeners(event);
     }
diff --git a/src/main/java/com/ericsson/gerrit/plugins/highavailability/index/ChangeCheckerImpl.java b/src/main/java/com/ericsson/gerrit/plugins/highavailability/index/ChangeCheckerImpl.java
index 23712be..945cefa 100644
--- a/src/main/java/com/ericsson/gerrit/plugins/highavailability/index/ChangeCheckerImpl.java
+++ b/src/main/java/com/ericsson/gerrit/plugins/highavailability/index/ChangeCheckerImpl.java
@@ -87,7 +87,7 @@
   @Override
   public Optional<ChangeNotes> getChangeNotes() {
     try (ManualRequestContext ctx = oneOffReqCtx.open()) {
-      changeNotes = Optional.ofNullable(changeFinder.findOne(changeId));
+      changeNotes = changeFinder.findOne(changeId);
       return changeNotes;
     }
   }
diff --git a/src/main/resources/Documentation/config.md b/src/main/resources/Documentation/config.md
index 5186bd1..3b1fee2 100644
--- a/src/main/resources/Documentation/config.md
+++ b/src/main/resources/Documentation/config.md
@@ -3,8 +3,8 @@
 =========================
 
 The @PLUGIN@ plugin must be installed on all the instances. Each instance should
-be configured with the same [gerrit.serverId](https://gerrit-documentation.storage.googleapis.com/Documentation/3.1.0/config-gerrit.html#gerrit.serverId).
-If there are existing changes in [NoteDb](https://gerrit-documentation.storage.googleapis.com/Documentation/3.1.0/note-db.html)
+be configured with the same [gerrit.serverId](https://gerrit-documentation.storage.googleapis.com/Documentation/3.2.0/config-gerrit.html#gerrit.serverId).
+If there are existing changes in [NoteDb](https://gerrit-documentation.storage.googleapis.com/Documentation/3.2.0/note-db.html)
 made with another `serverId`, then this plugin might not be able to access them.
 Likewise, if the HA gerrit.serverIds differ, then changes conveyed by one
 instance will not be accessible by the other.
@@ -238,3 +238,23 @@
 
 ```healthcheck.enable```
 :   Whether to enable the health check endpoint. Defaults to 'true'.
+
+File 'gerrit.config'
+--------------------
+
+```gerrit.instanceId```
+:   Optional identifier for this Gerrit instance.
+[[docs](https://gerrit-documentation.storage.googleapis.com/Documentation/3.2.0/config-gerrit.html#gerrit.instanceId)].
+
+Whilst this is not, specifically, a high-availability plugin configuration, it plays
+an important role on which events are forwarded to peers.
+
+If `instanceId` is set, events produced by that Gerrit instance will contain its
+origin in the `instanceId` field, allowing to track where they are coming from.
+
+The high-availability plugin will check the `instanceId` value to decide whether
+an event should be forwarded: events that originated from different Gerrit instances
+will not be forwarded.
+
+When neither `gerrit.instanceId` nor `event.instanceId` are set, it is not possible
+to identify the origin of the event and thus the event is always forwarded.
diff --git a/src/test/java/com/ericsson/gerrit/plugins/highavailability/autoreindex/GroupReindexRunnableTest.java b/src/test/java/com/ericsson/gerrit/plugins/highavailability/autoreindex/GroupReindexRunnableTest.java
index 5139a66..ce11242 100644
--- a/src/test/java/com/ericsson/gerrit/plugins/highavailability/autoreindex/GroupReindexRunnableTest.java
+++ b/src/test/java/com/ericsson/gerrit/plugins/highavailability/autoreindex/GroupReindexRunnableTest.java
@@ -194,13 +194,16 @@
   }
 
   private Optional<InternalGroup> getInternalGroup(Timestamp timestamp) {
-    AccountGroup accountGroup =
-        new AccountGroup(AccountGroup.nameKey("Test"), AccountGroup.id(1), uuid, timestamp);
     return Optional.ofNullable(
-        InternalGroup.create(
-            accountGroup,
-            ImmutableSet.<Id>builder().build(),
-            ImmutableSet.<UUID>builder().build(),
-            null));
+        InternalGroup.builder()
+            .setId(AccountGroup.Id.parse("1"))
+            .setNameKey(AccountGroup.nameKey("Test"))
+            .setOwnerGroupUUID(uuid)
+            .setVisibleToAll(true)
+            .setGroupUUID(UUID.parse("12"))
+            .setCreatedOn(timestamp)
+            .setMembers(ImmutableSet.<Id>builder().build())
+            .setSubgroups(ImmutableSet.<UUID>builder().build())
+            .build());
   }
 }
diff --git a/src/test/java/com/ericsson/gerrit/plugins/highavailability/cache/CacheEvictionHandlerTest.java b/src/test/java/com/ericsson/gerrit/plugins/highavailability/cache/CacheEvictionHandlerTest.java
new file mode 100644
index 0000000..7077319
--- /dev/null
+++ b/src/test/java/com/ericsson/gerrit/plugins/highavailability/cache/CacheEvictionHandlerTest.java
@@ -0,0 +1,63 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.ericsson.gerrit.plugins.highavailability.cache;
+
+import static org.mockito.Mockito.verifyZeroInteractions;
+import static org.mockito.Mockito.when;
+
+import com.ericsson.gerrit.plugins.highavailability.Configuration;
+import com.ericsson.gerrit.plugins.highavailability.forwarder.Forwarder;
+import com.google.common.cache.RemovalCause;
+import com.google.common.cache.RemovalNotification;
+import com.google.gerrit.server.config.PluginConfigFactory;
+import com.google.gerrit.server.config.SitePaths;
+import java.io.IOException;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.concurrent.Executor;
+import org.eclipse.jgit.lib.Config;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.junit.MockitoJUnitRunner;
+
+@RunWith(MockitoJUnitRunner.class)
+public class CacheEvictionHandlerTest {
+  @Mock private Executor executorMock;
+  @Mock private Forwarder forwarder;
+  @Mock private PluginConfigFactory pluginConfigFactoryMock;
+
+  private static final String PLUGIN_NAME = "high-availability";
+  private static final Path SITE_PATH = Paths.get("/site_path");
+  private CachePatternMatcher defaultCacheMatcher;
+
+  @Before
+  public void setUp() throws IOException {
+    when(pluginConfigFactoryMock.getGlobalPluginConfig(PLUGIN_NAME)).thenReturn(new Config());
+    defaultCacheMatcher =
+        new CachePatternMatcher(
+            new Configuration(pluginConfigFactoryMock, PLUGIN_NAME, new SitePaths(SITE_PATH)));
+  }
+
+  @Test
+  public void shouldNotPublishAccountsCacheEvictions() {
+    CacheEvictionHandler<String, String> handler =
+        new CacheEvictionHandler<>(forwarder, executorMock, PLUGIN_NAME, defaultCacheMatcher);
+    handler.onRemoval(
+        "test", "accounts", RemovalNotification.create("test", "accounts", RemovalCause.EXPLICIT));
+    verifyZeroInteractions(executorMock);
+  }
+}
diff --git a/src/test/java/com/ericsson/gerrit/plugins/highavailability/cache/CacheEvictionIT.java b/src/test/java/com/ericsson/gerrit/plugins/highavailability/cache/CacheEvictionIT.java
index e91e2ae..180c68f 100644
--- a/src/test/java/com/ericsson/gerrit/plugins/highavailability/cache/CacheEvictionIT.java
+++ b/src/test/java/com/ericsson/gerrit/plugins/highavailability/cache/CacheEvictionIT.java
@@ -26,13 +26,13 @@
 
 import com.github.tomakehurst.wiremock.junit.WireMockRule;
 import com.google.common.cache.LoadingCache;
-import com.google.gerrit.acceptance.GerritConfig;
-import com.google.gerrit.acceptance.GlobalPluginConfig;
 import com.google.gerrit.acceptance.LightweightPluginDaemonTest;
 import com.google.gerrit.acceptance.NoHttpd;
 import com.google.gerrit.acceptance.TestPlugin;
 import com.google.gerrit.acceptance.UseLocalDisk;
 import com.google.gerrit.acceptance.UseSsh;
+import com.google.gerrit.acceptance.config.GerritConfig;
+import com.google.gerrit.acceptance.config.GlobalPluginConfig;
 import com.google.gerrit.entities.AccountGroup;
 import com.google.inject.Inject;
 import com.google.inject.name.Named;
diff --git a/src/test/java/com/ericsson/gerrit/plugins/highavailability/cache/CachePatternMatcherTest.java b/src/test/java/com/ericsson/gerrit/plugins/highavailability/cache/CachePatternMatcherTest.java
index 9b6e66b..caf50b9 100644
--- a/src/test/java/com/ericsson/gerrit/plugins/highavailability/cache/CachePatternMatcherTest.java
+++ b/src/test/java/com/ericsson/gerrit/plugins/highavailability/cache/CachePatternMatcherTest.java
@@ -38,7 +38,6 @@
     CachePatternMatcher matcher = new CachePatternMatcher(configurationMock);
     for (String cache :
         ImmutableList.of(
-            "accounts",
             "groups",
             "groups_byinclude",
             "groups_byname",
@@ -55,6 +54,7 @@
     }
     for (String cache :
         ImmutableList.of(
+            "accounts",
             "adv_bases",
             "change_kind",
             "change_notes",
diff --git a/src/test/java/com/ericsson/gerrit/plugins/highavailability/cache/ProjectListIT.java b/src/test/java/com/ericsson/gerrit/plugins/highavailability/cache/ProjectListIT.java
index 22ef89e..98cdce5 100644
--- a/src/test/java/com/ericsson/gerrit/plugins/highavailability/cache/ProjectListIT.java
+++ b/src/test/java/com/ericsson/gerrit/plugins/highavailability/cache/ProjectListIT.java
@@ -25,11 +25,11 @@
 import static com.google.common.truth.Truth.assertThat;
 
 import com.github.tomakehurst.wiremock.junit.WireMockRule;
-import com.google.gerrit.acceptance.GlobalPluginConfig;
 import com.google.gerrit.acceptance.LightweightPluginDaemonTest;
 import com.google.gerrit.acceptance.NoHttpd;
 import com.google.gerrit.acceptance.TestPlugin;
 import com.google.gerrit.acceptance.UseLocalDisk;
+import com.google.gerrit.acceptance.config.GlobalPluginConfig;
 import com.google.gerrit.extensions.restapi.Url;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
diff --git a/src/test/java/com/ericsson/gerrit/plugins/highavailability/forwarder/ForwardedAwareEventBrokerTest.java b/src/test/java/com/ericsson/gerrit/plugins/highavailability/forwarder/ForwardedAwareEventBrokerTest.java
index 36cc953..cfe0475 100644
--- a/src/test/java/com/ericsson/gerrit/plugins/highavailability/forwarder/ForwardedAwareEventBrokerTest.java
+++ b/src/test/java/com/ericsson/gerrit/plugins/highavailability/forwarder/ForwardedAwareEventBrokerTest.java
@@ -30,7 +30,9 @@
 
   private EventListener listenerMock;
   private ForwardedAwareEventBroker broker;
-  private Event event = new TestEvent();
+  private ForwardedAwareEventBroker brokerWithGerritInstanceId;
+  private Event event;
+  private String gerritInstanceId = "gerrit-instance-id";
 
   @Before
   public void setUp() {
@@ -38,8 +40,11 @@
     listenerMock = mock(EventListener.class);
     DynamicSet<EventListener> set = DynamicSet.emptySet();
     set.add("high-availability", listenerMock);
+    event = new TestEvent();
     PluginSetContext<EventListener> listeners = new PluginSetContext<>(set, mockMetrics);
-    broker = new ForwardedAwareEventBroker(null, listeners, null, null, null);
+    broker = new ForwardedAwareEventBroker(null, listeners, null, null, null, null);
+    brokerWithGerritInstanceId =
+        new ForwardedAwareEventBroker(null, listeners, null, null, null, gerritInstanceId);
   }
 
   @Test
@@ -58,4 +63,43 @@
     }
     verifyZeroInteractions(listenerMock);
   }
+
+  @Test
+  public void shouldNotDispatchEventWhenEventInstanceIdIsDefinedButGerritInstanceIdIsNot() {
+    event.instanceId = gerritInstanceId;
+    try {
+      broker.fireEventForUnrestrictedListeners(event);
+    } finally {
+      Context.unsetForwardedEvent();
+    }
+    verifyZeroInteractions(listenerMock);
+  }
+
+  @Test
+  public void shouldNotDispatchEventWhenGerritInstanceIdIsDefinedButEventInstanceIdIsNot() {
+    try {
+      brokerWithGerritInstanceId.fireEventForUnrestrictedListeners(event);
+    } finally {
+      Context.unsetForwardedEvent();
+    }
+    verifyZeroInteractions(listenerMock);
+  }
+
+  @Test
+  public void shouldNotDispatchEventWhenInstanceIdsAreDifferent() {
+    event.instanceId = "some-other-gerrit-instance-id";
+    try {
+      brokerWithGerritInstanceId.fireEventForUnrestrictedListeners(event);
+    } finally {
+      Context.unsetForwardedEvent();
+    }
+    verifyZeroInteractions(listenerMock);
+  }
+
+  @Test
+  public void shouldDispatchEventWhenInstanceIdsAreEqual() {
+    event.instanceId = gerritInstanceId;
+    brokerWithGerritInstanceId.fireEventForUnrestrictedListeners(event);
+    verify(listenerMock).onEvent(event);
+  }
 }
diff --git a/src/test/java/com/ericsson/gerrit/plugins/highavailability/index/AbstractIndexForwardingIT.java b/src/test/java/com/ericsson/gerrit/plugins/highavailability/index/AbstractIndexForwardingIT.java
index af4637e..5843908 100644
--- a/src/test/java/com/ericsson/gerrit/plugins/highavailability/index/AbstractIndexForwardingIT.java
+++ b/src/test/java/com/ericsson/gerrit/plugins/highavailability/index/AbstractIndexForwardingIT.java
@@ -26,11 +26,11 @@
 import static com.google.common.truth.Truth.assertThat;
 
 import com.github.tomakehurst.wiremock.junit.WireMockRule;
-import com.google.gerrit.acceptance.GlobalPluginConfig;
 import com.google.gerrit.acceptance.LightweightPluginDaemonTest;
 import com.google.gerrit.acceptance.NoHttpd;
 import com.google.gerrit.acceptance.TestPlugin;
 import com.google.gerrit.acceptance.UseLocalDisk;
+import com.google.gerrit.acceptance.config.GlobalPluginConfig;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
 import org.apache.http.HttpStatus;