This code worked in the last release, but with the new dll, it seems that collision is either on or off...
Mesh.CreateBox(5, 5, 5, True)
Mesh.SetCollisionEnable(False, 1)
Mesh.SetCollisionEnable(False, 3)
Mesh.SetCollisionEnable(False, 5)
When SetCollisionEnable(...) isn't called, AdvancedCollision(...) returns true, but otherwise, no collision is detected for the whole mesh, not just the specified groups.