Index: lams_gradebook/src/java/org/lamsfoundation/lams/gradebook/service/GradebookService.java
===================================================================
diff -u -r5a5f3640c4d5fdf0c302347e7d6b502a972fd9cc -r246994a59d7c4ff0dfd17290461e112bedfc6545
--- lams_gradebook/src/java/org/lamsfoundation/lams/gradebook/service/GradebookService.java	(.../GradebookService.java)	(revision 5a5f3640c4d5fdf0c302347e7d6b502a972fd9cc)
+++ lams_gradebook/src/java/org/lamsfoundation/lams/gradebook/service/GradebookService.java	(.../GradebookService.java)	(revision 246994a59d7c4ff0dfd17290461e112bedfc6545)
@@ -335,8 +335,15 @@
 	return gradebookDAO.getGradebookUserDataForActivity(activityID, userID);
     }
 
-    public Double getAverageMarkForActivity(Long activityID) {
-	return gradebookDAO.getAverageMarkForActivity(activityID);
+    public Double getAverageMarkForActivity(Long activityID, Long groupID) {
+	//return AverageMarkForActivity if groupId is null and AverageMarkForGroupedActivity if groupId is specified
+	Double averageMark;
+	if (groupID == null) {
+	    averageMark = gradebookDAO.getAverageMarkForActivity(activityID);
+	} else {
+	    averageMark = gradebookDAO.getAverageMarkForGroupedActivity(activityID, groupID);
+	}
+	return averageMark;
     }
 
     public Double getAverageMarkForLesson(Long lessonID) {
Index: lams_gradebook/src/java/org/lamsfoundation/lams/gradebook/service/IGradebookService.java
===================================================================
diff -u -r5a5f3640c4d5fdf0c302347e7d6b502a972fd9cc -r246994a59d7c4ff0dfd17290461e112bedfc6545
--- lams_gradebook/src/java/org/lamsfoundation/lams/gradebook/service/IGradebookService.java	(.../IGradebookService.java)	(revision 5a5f3640c4d5fdf0c302347e7d6b502a972fd9cc)
+++ lams_gradebook/src/java/org/lamsfoundation/lams/gradebook/service/IGradebookService.java	(.../IGradebookService.java)	(revision 246994a59d7c4ff0dfd17290461e112bedfc6545)
@@ -157,12 +157,14 @@
     GradebookUserActivity getGradebookUserActivity(Long activityID, Integer userID);
     
     /**
-     * Returns the average mark for a given activity
+     * Returns the average mark for a given activity. Activity can be grouped - then supply according groupId to receive
+     * AverageMarkForGroupedActivity.
      * 
      * @param activityID
+     * @param groupID return AverageMarkForActivity if groupId is null and AverageMarkForGroupedActivity if groupId is specified
      * @return
      */
-    Double getAverageMarkForActivity(Long activityID);
+    Double getAverageMarkForActivity(Long activityID, Long groupID);
     
     /**
      * Returns the average mark for a lesson
Index: lams_gradebook/src/java/org/lamsfoundation/lams/gradebook/web/action/GradebookAction.java
===================================================================
diff -u -rb7097f75fa02948b4092c56103ea3eb853297016 -r246994a59d7c4ff0dfd17290461e112bedfc6545
--- lams_gradebook/src/java/org/lamsfoundation/lams/gradebook/web/action/GradebookAction.java	(.../GradebookAction.java)	(revision b7097f75fa02948b4092c56103ea3eb853297016)
+++ lams_gradebook/src/java/org/lamsfoundation/lams/gradebook/web/action/GradebookAction.java	(.../GradebookAction.java)	(revision 246994a59d7c4ff0dfd17290461e112bedfc6545)
@@ -389,20 +389,21 @@
 	String rowID = WebUtil.readStrParam(request, AttributeNames.PARAM_ACTIVITY_ID);
 	
 	Long activityID = null;
+	Long groupID = null;
 	
 	// Splitting the rowID param to get the activity/group id pair
 	String[] split = rowID.split("_");
 	if (split.length == 2) {
 	    activityID = Long.parseLong(split[0]);
+	    groupID = Long.parseLong(split[1]);
 	} else {
 	    activityID = Long.parseLong(rowID);
 	}
 	
     	Activity activity = gradebookService.getActivityById(activityID);
     	
     	if (activity != null) {
-    	    Double averageMark = gradebookService.getAverageMarkForActivity(activityID);
-
+    	    Double averageMark = gradebookService.getAverageMarkForActivity(activityID, groupID);
     	    
     	    if (averageMark != null) {
     		writeResponse(response, CONTENT_TYPE_TEXT_PLAIN, ENCODING_UTF8, averageMark.toString());