private void CreateReplacementEdge(INode sourceNode, INode targetNode, IEdge edge)
 {
     if ((AggregateGraph.IsAggregationItem(sourceNode) || AggregateGraph.IsAggregationItem(targetNode)) &&
         AggregateGraph.GetEdge(sourceNode, targetNode) == null &&
         AggregateGraph.GetEdge(targetNode, sourceNode) == null)
     {
         AggregateGraph.CreateEdge(sourceNode, targetNode, edge.Style);
     }
 }