Multiple Assembly Instances

Okay - I've been out of SolidWorks for a while now but now I'm back, and can't for the life of me figure this out.  I have a glass pane sub-assembly inserted in two places within an assembly.  The main assembly is a window frame containing one fixed window, and three operable windows.  The glass pane is inserted into the frame as the fixed window.  The operable windows are assemblies containing the glass pane assembly.

My problem is this:  I control the glass pane sizing via equations in the operable window assemblies, and from the main frame assembly.  The problem is I get one or the other - can't seem to have them size independently based what assembly they are attached to.  I keep thinking this has something to do with configurations which for some reason are really baffling me. Sorry for such a newbie question, but I've been combing through the posts and can't seem to find quite what I'm after...

Thanks

Todd

SolidworksAssemblies