This is an XY answer, giving you a solution to what you want to achieve, rather than answering the actual question about automating mutes. Let the downvotes commence…!
I would advise against using mute for this purpose as you might get clicks with these instant changes of volume. There a few better ways to do this:
- automate the volume with very short ramps up and down
- use an inverted noise gate (set as a “ducker”) side chained to another track that plays notes whenever you want the gaps in your other tracks. Something with a constant volume, like a simple synth, would work well for this. The advantage of this method is that you can subtly change the attack, release, threshold, hold etc. on the noise gate to get exactly the sound you want.
Most importantly though, whichever method you choose to use for this ducking, it is much easier to apply this to multiple tracks by first sending them all to one Aux track.