It would be really great if DOPs understood sop groups…

eg
a grid
half in groupA half in groupB
in DOPs make groupA cloth…

I think you can do this, but you'd have to either build your own version of the Cloth Object, or else edit the Cloth Object that you're using. Because in the SOP Geometry node that grabs the geometry, there is a field for specifying a Group. It's just not used by the default Cloth Object OTL.

thanks craig…I'll see what I can do