Live shape keys

Hi guys, I was wandering if anyone knows about a way to make live shape keys, what I mean by this is having a shape key referencing constantly a “source” objects, and any change or animation on the source would be immediately updated on the shape key holder.

this is very useful for things like dorito set-ups or doing convenient facial set ups where every complex part is rigged in a different mesh and then they are all “merged” in a “renderable” master mesh via live shape keys.

It has other uses obviously but it mainly gives us a lot of flexibility.

anyone knows anything about this?

What you’re looking for is called a Driver