Animating a character made of multiple objects

Hi

I'm toying with an idea where I may have a character (humanoid) made by combining multiple mesh parts e.g. 5 different models of legs,head,torso,arms I make a character with head1,arms3,torso2,legs5. Can this be animated easily with mecanim as I have a number of animations from the asset store?

I've done some searches but cant find any information on this?. Is there some way to inform mecanim that (for example) the shoulder bone in the torso model links to the shoulder bone in the arm model, in which case should I duplicate the bone between the two models (arm and torso both have the "shoulderL1" bone for example).

Or is it faster/possible to combine all the meshes into one at runtime and rebuild the mesh should a change occur (legs1 changed to legs3)?

Thanks in advance for any help.