Momentary Choke mode

Choke groups (sharing channel) are super, but would be nice to have an alternate mode where pressing B mutes A while B is pressed, then A continues (not retriggered) when releasing B. Particularly useful for loops where you can drop in a few beats of another loop of the same tempo on the same channel, then release B and come back to A where it was playing in the background all along. Sort of like transform/x-fader buttons?