Auto Layout Nodes Within A Subgraph?

We want to have Nodes and Links between them in one SubGraph and another set of Nodes and Links in another SubGraph -- plus, we need to have some of the Nodes w/in a SubGraph link to Nodes in another SubGraph. And ... to the point: we need to have these SubGraphs automatically laid out and have the Nodes within them automatically laid out. (QUESTION: I assume SubGraphs are the way to go for containing other Nodes?)
Without the subgraphs, the layout manager lays the nodes and links ok. With the subgraphs, it lays out the SubGraphs ok but not the Nodes w/in the SubGraph. I was hoping that I could first layout the SubGraphs w/ a layout manager and then use a layout manager to layout each of the SubGraphs but ...

Anyone know how to get what we need? Thx -- Bill
e.g. the following test code is in our own class that extends GoDocument (it's pared down for testing):
// Create 4 Nodes
GoIconicNode n1 = new GoIconicNode();
GoIconicNode n2 = new GoIconicNode();
GoIconicNode n3 = new GoIconicNode();
GoIconicNode n4 = new GoIconicNode();
// Create 2 SubGraphs, add Nodes to them, add the Nodes to the SubGraphs
GoSubGraph sg1 = new GoSubGraph();
GoSubGraph sg2 = new GoSubGraph();
// Add the subgraphs to the Document
// Layout the Document which contains the 2 SubGraphs
GoLayoutLayeredDigraph layout = new GoLayoutLayeredDigraph();
layout.Document = this;

Have you looked at the Layout code in the SubGraphApp sample?