I hadn't thought of OBJ2CR2 specifically, but I had given AutoGroup Editor a go at one point, which works on similar methods I believe.  It won't do the complete job, eyes, jaw, etc would be missed, but it would help with some of the larger areas (chest, hip, etc).

I was hoping there may be a way to auto create groups based on the colors of a texture template, but I'm not finding such an option anywyere.