Additive animation as an offset and not as an absolute.

Is there a way to add animation as an offset of the current joint location based on local position and not as an absolute world value?

I have a few character rigged for facial animation where I can position the facial bones relative to the current character but when I apply an animation based on the original rig it causes the modified mesh to distort based on the absolute animation. What I would like to do is use the off set transforms of + or - of the current local position and not the world position.