Try putting COMM2 (ATIS) on the cabin speaker instead of the intercom.
This is what the KX-155A does.

Steven Barnes wrote:
Ah, I like that technique. Gotta try that next time.
Better than my technique I used last weekend: Turn down volume on Comm1 to
listen to ATIS on Comm2, then forget to turn up volume on Comm1 again. Makes
for a fun conversation when you finally turn up the volume again...