It's best to do the "slicing" in your modeling program rather than in Poser or even more difficult by hand with a text editor. I use Lightwave and I do the body parts assignment within Lightwave before it is imported to Poser. I've played with a friend's Poser Pro Pack. If you are seriously considering doing more conformable clothes, then little dragon is correct. With Pro Pack you can just ignore all the tutorials on the web and start creating your own conforming geometry as much as you want. It really simplifies the process exponentially.