best to send feature requests via the contact page on the squarp web site.
I’ll be honest, I cannot see how this would work, not really space in the UI in any mode…
so when you send in the request, you might want to include some suggestions, on how you think this could work. 
you have two options you have today:
- use a pedal, this has the option to do next/prev track (so zero hands )
- use another midi controller, and turn on pyramidi , then CC0 can select track
https://squarp.net/static/PYRAMiDi-7094a08cfe1165baf6db2b8207409fbe.pdf
the other option (depending on what you are trying to do exactly) is to use the omnimode=multtrack bank A (etc) option (see manual/settings)
this way your controller can send midi on different channels to play on different tracks.