What you are trying to do is easy in a DAW. In BiaB have the piano play for the whole measure. Drag and drop the tracks into a DAW. On that measure use volume automation to fade the piano, then at the start of the next measure sharply bring the volume back to normal.

Whenever I get something stuck in the back of my throat, I dislodge it by drinking a beer.
It's called the Heineken Maneuver.

64 bit Win 10 Pro, the latest BiaB/RB, Roland Octa-Capture audio interface, a ton of software/hardware