Masking/Disabling mocap data on limbs

Hey there, I have 2 pieces of mocap data I am looking to “merge”. One is a walking animation and the other is a standing while gesturing with hands.

My goal is to remove the arm swing and head bob in the walking animation and replace it will the arm gesturing and head nodding of the talking animation. So, I would like to “toggle” off the arms and head from the walk cycle and turn on the arms and head in the talking animation.

I figure i could manually delete keys, but ideally i would be able to transition from the full walk into just the animation of the arms and head of the talking animation, while keeping the legs of the walk cycle going.