How to non uniformly scale a skeletal meshes proportions

I currently have several skeletal meshes that are all using the same skeleton but have different body proportion (wider hips, narrower shoulders, etc), I’m trying to find a way to scale the different body proportions down to match the base proportions at certain times, such as a grapple between two of the character to help the characters attach to each other better, I know I can use the transform bone node to do so but was wondering if there was a way to scale them using some sort of additive pose.