One question that is askeda lot is:

"Why can't I save a prop as a smart prop?"

The usual reason for this not working is that you have used "Select Subset" when saving the prop. When the subset option is used, you won't get the option to save as a smart prop.

A related question is:

"How do I make a smart prop that contains multiple objects?"

Assuming that all the objects are part of a parenting chain that ultimatly links to one object, use "Select Subset" to include all the objects in one pp2 (prop file). Then open the pp2 in a text editor. Find the line that says "parent UNIVERSE" and change it to read "smartparent NameOfParent", eg:

smartparent rHand
or
smartparent head
or
smartparent box_1

Note that when you save the prop from Poser, you must have "Use file compression" turned off in your General Preferences. This ensures that the resulting file is a pp2, not a ppz.