I think you would have to export it as an object, re import it and then set up the heirarchy and joint parameters again. Probably not worth it. It is somthing you might want to bring upo on the next Poser wish list. I have used Max and the collapse modifier stack is similar to what you're talking about I think. It would be nice. Maybe there's a way I haven't thought of.

"Your work is to keep cranking the flywheel that turns the gears that spin the belt in the engine of belief that keeps you and your desk in midair."

Annie Dillard