I think that there's a misunderstanding, MED offers the functionality of Groups, it even has a Group Mode along with Vertex and Triangle Mode. Those groups are in fact distinct meshes (/ mesh groups/ subsets) that can be f.i. disabled in the engine via vmask.

Then there's another thing called group in the MDL7 SDK, it allows something different like in WMB files, but has nothing to do with the current mesh group feature in MED (and the engine). Correct?