Change collision mask at runtime? (Physics Behavior)

Is this already possible, and if not, could it be added sometime in the future?

I'm going to try to figure out a workaround in the meantime but there could be some situations where being able to switch from elipse to bounding box etc. at runtime could be useful.

Actually... never mind. It really isn't that important for my project (unless someone knows of a specific instance that it might be useful).

BUMP! I have a sprite with different shapes in different frames, one of them is a circle, would be great to change the collision mask to circle at runtime. Families wont work in my scenario