@ bagginsbill,

Quote - Is that statement from experience or a rumor you heard?

On my part, and in respect to P6, it is from experience. Try this pz2 file out. Select any actor of any figure and apply it. The selected actor's existing grouping will be rewritten, note that after applying the pose, you will need to select a different actor, then return to the original actor, in order to refresh the pallet.

{

version
    {
    number 6
    }

actor $CURRENT
    {
    channels
        {
        groups
            {
            groupNode New Group
                {
                parmNode New Node
                }
            }
        }
    }
}

In the absence of existing grouping, Poser will write its own grouping. So there will  be group "Transform" for translations, rotations, and scale, and any un-grouped morphs will be put in a group named "Morph".