Blending multiple animations

We have a character with a blendspace set up for idle/walking/running in a state machine (currently the only thing there but will be adding more) + have added a layered blend per bone above the waist for melee animations playing on a certain slot. All of this is working fine. What we would like to do is be able to further blend in damage anim sequences (front, rear, left, right animations). We would like to account for the following possibilities:

  • Moving normally & taking damage simultaneously
  • Attacking (may or may not be moving) & taking damage simultaneously

Playing multiple montages is apparently out at this time. I can’t add the damage animations to my state machine without it throwing away my current movement blend.

How would others approach/tackle these requirements?