I, too, use Auto Group Editor.  I find the Poser grouping tool to be too "iffy" with grouping.  As an example.....I recently grouped a Dusk set in Poser.  The shirt grouped fine, the pants, not so much.  The pants were an awful mess when grouped that way.

Poser assumes "conventional" grouping, so when you are rigging in an unconventional way, you can't use Poser to rig.  A perfect example is a skirt where you want the thighs to follow a weight mapped figure.  Grouping in Poser groups the thighs into the skirt, resulting in a broken rig.