diff --git a/src/helma/objectmodel/Relation.java b/src/helma/objectmodel/Relation.java
index cb4341a6..5127c01d 100644
--- a/src/helma/objectmodel/Relation.java
+++ b/src/helma/objectmodel/Relation.java
@@ -229,6 +229,7 @@ public class Relation {
 	    throw new RuntimeException ("getVirtualPropertyRelation called on non-virtual relation");
 	Relation vr = new Relation (other, localField, remoteField, direction, subnodesAreProperties);
 	vr.groupby = groupby;
+	vr.filter = filter;
 	return vr;
     }
 
@@ -236,10 +237,6 @@ public class Relation {
      * Return a Relation that defines the subnodes of a group-by node.
      */
     public Relation getGroupbySubnodeRelation () {
-	if (groupby == null)
-	    throw new RuntimeException ("getGroupbySubnodeRelation called on non-group-by relation");
-	if (filter != null)
-	    return filter;
 	return getGroupbyPropertyRelation ();
     }
 
@@ -249,6 +246,8 @@ public class Relation {
     public Relation getGroupbyPropertyRelation () {
 	if (groupby == null)
 	    throw new RuntimeException ("getGroupbyPropertyRelation called on non-group-by relation");
+	if (filter != null)
+	    return filter;
 	return new Relation (other, localField, remoteField, direction, subnodesAreProperties);
     }