.asm structure including merged parts

When looking at the structure tab of a .asm file, it doesn't show any of the merged models. Is there a way to show this?

We have many cases where a forging is merged into a .prt to create the machining features. Of course, .prt files don't have a structure tab, However, in the related objects tab in the References table it does show the forging used.

I have been unable to figure out how to show the forging (related object) int he structure tab of my assemblies. We know the link is tracked by Windchill, so now we just need it to show an accurate assembly structure.

Any ideas or hints?