See the little upside down triangle drop down, near the top of the Group Tool Palette, that says "polSurface...?"  WHat happens when you open tht drop down, how many groups are there?  THat is the list of Groups(/Material ZOnes) you have in that object.

With that Pallette you could Edit the ones that are there, dlete them, and/or create new one.

FYI - Material Zones define what part of the surface will be texture(Like V3.)