I think it would be very useful if we could combine the static mesh physics option for a part of the model and manually set physics for another part, and then have the resulted physic shape for the object. - without splitting the object itself.

For ex, If I have a high poly chain as part of a ship, I can chose either to have no physics for the chain or a very high physics with holes for every link in the chain resulting in a very complex physic shape.

Another example is stairs integrated into higher objects.
I would like to have a box physic shape for stairs to make sure they're climbable, and static mesh for the rest, without having to edit the stairs as a separated model.