True dynamic cloth is not grouped.  It is a single sided mesh object generally stored in pp2 format.

There is hybrid clothing which is a combination of conforming groups and a single group (usually a skirt) that can be posed dynamically.  CP has a number of hybrid clothing items for the G2 figures.

If you are using conforming clothing, you can only clothify a single group for a single sim.

There is tutorial that dates back to Poser 5 by PhilC on the SMS official Poser site that explains how to take conforming clothing and turn it into dynamic clothing.