diff --git a/src/main/java/com/googlesource/gerrit/plugins/task/TaskConfig.java b/src/main/java/com/googlesource/gerrit/plugins/task/TaskConfig.java
index f5f0bd4..56cdd88 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/task/TaskConfig.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/task/TaskConfig.java
@@ -27,6 +27,7 @@
 import java.util.Map;
 import java.util.Optional;
 import java.util.Set;
+import java.util.stream.Collectors;
 
 /** Task Configuration file living in git */
 public class TaskConfig extends AbstractVersionedMetaData {
@@ -63,7 +64,7 @@
     public String preloadTask;
     public Map<String, String> properties;
     public String readyHint;
-    public List<String> subTasks;
+    public List<TaskKey> subTasks;
     public List<String> subTasksExternals;
     public List<String> subTasksFactories;
     public List<String> subTasksFiles;
@@ -85,7 +86,10 @@
       preloadTask = getString(s, KEY_PRELOAD_TASK, null);
       properties = getProperties(s, KEY_PROPERTIES_PREFIX);
       readyHint = getString(s, KEY_READY_HINT, null);
-      subTasks = getStringList(s, KEY_SUBTASK);
+      subTasks =
+          getStringList(s, KEY_SUBTASK).stream()
+              .map(subtask -> TaskKey.create(s.file(), subtask))
+              .collect(Collectors.toList());
       subTasksExternals = getStringList(s, KEY_SUBTASKS_EXTERNAL);
       subTasksFactories = getStringList(s, KEY_SUBTASKS_FACTORY);
       subTasksFiles = getStringList(s, KEY_SUBTASKS_FILE);
diff --git a/src/main/java/com/googlesource/gerrit/plugins/task/TaskKey.java b/src/main/java/com/googlesource/gerrit/plugins/task/TaskKey.java
index bd0b683..6b8f486 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/task/TaskKey.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/task/TaskKey.java
@@ -52,6 +52,10 @@
     return subSection().file().branch();
   }
 
+  public FileKey file() {
+    return subSection().file();
+  }
+
   public abstract SubSectionKey subSection();
 
   public abstract String task();
diff --git a/src/main/java/com/googlesource/gerrit/plugins/task/TaskTree.java b/src/main/java/com/googlesource/gerrit/plugins/task/TaskTree.java
index 44fcadc..d5ab48e 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/task/TaskTree.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/task/TaskTree.java
@@ -365,10 +365,11 @@
       }
 
       protected void addSubTasks() throws IOException, StorageException {
-        for (String expression : task.subTasks) {
+        for (TaskKey taskKey : task.subTasks) {
           try {
             Optional<Task> def =
-                preloader.getOptionalTask(taskExpressionFactory.create(task.file(), expression));
+                preloader.getOptionalTask(
+                    taskExpressionFactory.create(taskKey.file(), taskKey.task()));
             if (def.isPresent()) {
               addPreloaded(def.get());
             }
diff --git a/src/main/java/com/googlesource/gerrit/plugins/task/properties/AbstractExpander.java b/src/main/java/com/googlesource/gerrit/plugins/task/properties/AbstractExpander.java
index c970cec..1c9ef43 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/task/properties/AbstractExpander.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/task/properties/AbstractExpander.java
@@ -14,7 +14,9 @@
 
 package com.googlesource.gerrit.plugins.task.properties;
 
+import com.googlesource.gerrit.plugins.task.TaskKey;
 import java.lang.reflect.Field;
+import java.lang.reflect.ParameterizedType;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
@@ -101,11 +103,24 @@
           field.set(cow.getForWrite(), expanded);
         }
       } else if (o instanceof List) {
-        @SuppressWarnings("unchecked")
-        List<String> forceCheck = List.class.cast(o);
-        List<String> expanded = expand(forceCheck);
-        if (expanded != o) {
-          field.set(cow.getForWrite(), expanded);
+        ParameterizedType parameterizedType = (ParameterizedType) field.getGenericType();
+        Class<?> classType = (Class<?>) parameterizedType.getActualTypeArguments()[0];
+        if (classType == String.class) {
+          @SuppressWarnings("unchecked")
+          List<String> forceCheck = List.class.cast(o);
+          List<String> expanded = expand(forceCheck);
+          if (expanded != o) {
+            field.set(cow.getForWrite(), expanded);
+          }
+        } else if (classType == TaskKey.class) {
+          @SuppressWarnings("unchecked")
+          List<TaskKey> forceCheck = List.class.cast(o);
+          List<TaskKey> expanded = expandTaskKey(forceCheck);
+          if (expanded != o) {
+            field.set(cow.getForWrite(), expanded);
+          }
+        } else {
+          throw new RuntimeException(String.format("Unknown list type: %s", classType));
         }
       }
     } catch (IllegalAccessException e) {
@@ -118,6 +133,29 @@
    * Returns expanded unmodifiable List if property found. Returns same object if no expansions
    * occurred.
    */
+  public List<TaskKey> expandTaskKey(List<TaskKey> list) {
+    if (list != null) {
+      boolean hasProperty = false;
+      List<TaskKey> expandedList = new ArrayList<>(list.size());
+      for (TaskKey value : list) {
+        String expanded = expandText(value.task());
+        boolean hasExpanded = (value.task() != expanded);
+        hasProperty = hasProperty || hasExpanded;
+        if (hasExpanded) {
+          expandedList.add(TaskKey.create(value.file(), expanded));
+        } else {
+          expandedList.add(value);
+        }
+      }
+      return hasProperty ? Collections.unmodifiableList(expandedList) : list;
+    }
+    return null;
+  }
+
+  /**
+   * Returns expanded unmodifiable List if property found. Returns same object if no expansions
+   * occurred.
+   */
   public List<String> expand(List<String> list) {
     if (list != null) {
       boolean hasProperty = false;
diff --git a/src/main/resources/Documentation/test/task_states.md b/src/main/resources/Documentation/test/task_states.md
index 2df1263..dbe6fac 100644
--- a/src/main/resources/Documentation/test/task_states.md
+++ b/src/main/resources/Documentation/test/task_states.md
@@ -2451,6 +2451,144 @@
    ]
 }
 
+[root "Root Preload from all-projects sub-dir"]
+  preload-task = //dir/common.config^Sample relative task in sub dir
+
+{
+   "applicable" : true,
+   "hasPass" : true,
+   "name" : "Root Preload from all-projects sub-dir",
+   "status" : "PASS"
+}
+
+[root "Root Preload from all-projects sub-dir which has subtask in same file"]
+  preload-task = //dir/common.config^Sample relative task in sub dir with subtask from same file
+
+{
+   "applicable" : true,
+   "hasPass" : true,
+   "name" : "Root Preload from all-projects sub-dir which has subtask in same file",
+   "status" : "PASS",
+   "subTasks" : [
+      {
+         "applicable" : true,
+         "hasPass" : true,
+         "name" : "Sample relative task in sub dir",
+         "status" : "PASS"
+      }
+   ]
+}
+
+[root "Root Preload from all-projects sub-dir which has subtask in different file"]
+  preload-task = //dir/common.config^Sample relative task in sub dir with subtask from different file
+
+{
+   "applicable" : true,
+   "hasPass" : true,
+   "name" : "Root Preload from all-projects sub-dir which has subtask in different file",
+   "status" : "PASS",
+   "subTasks" : [
+      {
+         "applicable" : true,
+         "hasPass" : true,
+         "name" : "Passing task",
+         "status" : "PASS"
+      }
+   ]
+}
+
+[root "Root Preload from user ref"]
+  preload-task = @testuser/dir/relative.config^Relative Task
+
+{
+   "applicable" : true,
+   "hasPass" : true,
+   "name" : "Root Preload from user ref",
+   "status" : "PASS"
+}
+
+[root "Root Preload from user ref which has subtask in same file"]
+  preload-task = @testuser/dir/relative.config^Relative Task with subtask
+
+{
+   "applicable" : true,
+   "hasPass" : true,
+   "name" : "Root Preload from user ref which has subtask in same file",
+   "status" : "PASS",
+   "subTasks" : [
+      {
+         "applicable" : true,
+         "hasPass" : true,
+         "name" : "Passing task",
+         "status" : "PASS"
+      }
+   ]
+}
+
+[root "Root Preload from user ref which has subtask in different file"]
+  preload-task = @testuser/dir/relative.config^Import All-Projects root task
+
+{
+   "applicable" : true,
+   "hasPass" : false,
+   "name" : "Root Preload from user ref which has subtask in different file",
+   "status" : "PASS",
+   "subTasks" : [
+      {
+         "applicable" : true,
+         "hasPass" : true,
+         "name" : "Subtask PASS",
+         "status" : "PASS"
+      }
+   ]
+}
+
+[root "Root Preload from group ref"]
+  preload-task = %{non_secret_group_name_without_space}^task in group root config file 1
+
+{
+   "applicable" : true,
+   "hasPass" : true,
+   "name" : "Root Preload from group ref",
+   "status" : "PASS"
+}
+
+[root "Root Preload from group ref which has subtask in same file"]
+  preload-task = %{non_secret_group_name_without_space}^task in group root with subtask
+
+{
+   "applicable" : true,
+   "hasPass" : true,
+   "name" : "Root Preload from group ref which has subtask in same file",
+   "status" : "PASS",
+   "subTasks" : [
+      {
+         "applicable" : true,
+         "hasPass" : true,
+         "name" : "Passing task",
+         "status" : "PASS"
+      }
+   ]
+}
+
+[root "Root Preload from group ref which has subtask in different file"]
+  preload-task = %{non_secret_group_name_without_space}^task in group root with subtask from all-projects
+
+{
+   "applicable" : true,
+   "hasPass" : true,
+   "name" : "Root Preload from group ref which has subtask in different file",
+   "status" : "PASS",
+   "subTasks" : [
+      {
+         "applicable" : true,
+         "hasPass" : true,
+         "name" : "Subtask PASS",
+         "status" : "PASS"
+      }
+   ]
+}
+
 [root "Root INVALID Preload"]
   preload-task = missing
 
@@ -3045,6 +3183,10 @@
 ```
 [task "Root Import task from subdir using relative syntax"]
     subtask = dir/common.config^Sample relative task in sub dir
+
+[task "Passing task"]
+    applicable = is:open
+    pass = True
 ```
 
 file: `All-Projects:refs/meta/config:task/dir/common.config`
@@ -3053,6 +3195,16 @@
     applicable = is:open
     pass = is:open
 
+[task "Sample relative task in sub dir with subtask from same file"]
+    applicable = is:open
+    pass = is:open
+    subtask = Sample relative task in sub dir
+
+[task "Sample relative task in sub dir with subtask from different file"]
+    applicable = is:open
+    pass = is:open
+    subtask = //relative.config^Passing task
+
 [task "Root Import task from root task.config"]
     applicable = is:open
     subtask = ^Subtask PASS
@@ -3268,6 +3420,15 @@
   applicable = is:open
   pass = is:open
 
+[task "Relative Task with subtask"]
+  applicable = is:open
+  pass = is:open
+  subtask = Passing task
+
+[task "Passing task"]
+  applicable = is:open
+  pass = True
+
 [task "Import All-Projects root task"]
   applicable = is:open
   subtask = //^Subtask PASS
@@ -3319,6 +3480,20 @@
   applicable = is:open
   pass = is:open
 
+[task "task in group root with subtask"]
+  applicable = is:open
+  pass = is:open
+  subtask = Passing task
+
+[task "Passing task"]
+  applicable = is:open
+  pass = True
+
+[task "task in group root with subtask from all-projects"]
+  applicable = is:open
+  pass = is:open
+  subtask = //^Subtask PASS
+
 [task "task in group root config file 2"]
   applicable = is:open
   pass = is:open