How can I copy specific bone animation to a different transform in the hierarchy?

I have a full body character and I want to animate a custom bone for each hand so that I can attach the actual hand bones to them with IK. How do I copy the animation for the hand bones and apply it to these IK bones so they have the same identical orientation as the hands? I obviously can't just copy over the keyframes because the position/rotations are in local space. Any ideas?