The Desired Result: an object similar to a planet with a ring around it; both the planet and ring are solids, and both must move together, as if they were one object. The ring must be able to grow and shrink while the planet remains one size, so they can't be a single sprite.
The Problem: if I try to use bone movement to set one of the objects as a bone to the other, ball physics doesn't seem to work properly. If I set one object's position to the other, that object will not react as a solid.
Potential Solutions: the only thing that comes to mind is making the entire object a single sprite, and using animations with per-pixel collision detection to expand and contract the ring. This will result in A LOT of animations, which is why I'm trying to find a simpler way in which the two sprites can move together but both react to collisions as solids.