If you look in the 'P4 Nude Woman.cr2' at the hand actors, you will see three special channel types, handGrasp, thumbGrasp, and handSpread. These are the channels that Poser uses to control the grasping and spreading. If the hand is rigged in the same way as the P4 Nude Woman, with the same actor names and rotation order for the finger joints, you can just copy those three channels (using a cr2 editor, or text editor), and paste them into the hands of your own figure.

As I said, this will only work properly if the hands are done in the same way as in the P4 figures. In my next post, I will say a little about how to do it using ERC.