Well I'm not too sure about combining the props making your scene less heavy for Poser, but I may be wrong on that (somebody check me please, and not too hard against the boards! )
I do know that if you import an obj and make a prop of it that Poser embeds the obj as code to your pp2 file, that makes the file somewhat heavy. It's better to have the pp2 file (prop file) call for the obj where ever it resides in the Runtime folder structure. But I'm looking at this as a developer and not too sure if the rendering side cares one way or another.

So basically I don't know one way or another but just wanted to try and help.

Missy Woot!