Blendshape using vertex colors

Hello.

Normally when a model is imported with blendshapes, there’s just 1 slider that morphs one mesh shape into another, is there a way to only blend the areas that are painted with a different vertex color?

Everything is possible of course, but unless it needs to be generated realtime just make the blendshape animation only for those verts in your animation tool

It needs to be realtime in the game to create a body damage effect.

Could you maybe explain what exactly needs to happen?