Mesh fitting

I'm looking for a better way to precisely and easyly fit meshes one each other. Currently using a technique consisting in shinkwraping one object into another and converting it as a shape key. This is a problem when both are the same object (hand in belly p. ex.), you have to divide it. Is there any plug-in doing that and with adaptative subdivision in the contact edges? Is there a way that you can adjust one mesh to another but without deformation, modifying bones position? some kind of magnet meshes but keeping shapes. You may think in physics and collision, but that's slow and not precise.