couple options.

Poser can import 3ds and LWO objects. 3ds' sometimes group weird in Poser on direct import LWO IMO work better. I suggest sizing it and then exporting it back out. Then reload the prop without resizing it, use the grouping tool to seperate the parts into what you want to be movable then you can use "spawn Props" in the grouping tool to spawn each of those groups as individual props. place them rig it in the heirarchy and then save as a cr2.