AFAIK, Poser can't do that.

Sure enough, the Grouping Tool will allow you to create props but you'll be left with the original obj plus props.  Seems like a tedious waste of time when it's simpler to split them all up first and assign meaningful material names in your modelling app.

But that's just me; I don't like unnecessary work.  :) 

Coppula eam se non posit acceptera jocularum.

My Store

My Gallery