Maya Muscle provides a separate Muscle Multi Collide deformer that can be applied to multiple objects or single objects. This allows you to create object-object collision effects, and to use Maya Muscle’s Self Collision ability on surfaces.

Since this is a regular Maya deformer, there is only one paintable weight type, and that is the built-in Maya deformer weights. These weights are used to set rigidity on the object, rather than for culling or envelope effects.