Korg SQ64, managing midi input channel

Hi, I picked up a Korg SQ64 today and after a bit of fiddling around and a lot of googling have got it mostly working quite nicely.

The issue I'm encountering is that I want live MIDI input from a single keyboard (Yamaha CS reface) to toggle between controlling two synths on tracks A and B (the reface itself + a Monologue). Because you can't easily change the MIDI TX channel on the reface, it seems the easiest way to do this is to have MIDI RX disabled for one of the SQ64 tracks, then when I want to switch, disable it for the current track and reenable it for the other. This way, exactly one synth will receive the live MIDI input.

However, this is also a little cumbersome. Ideally I could always have MIDI RX enabled for both tracks, and use a single button press on the SQ64 to pick which synth it actually sends the live MIDI to. The documentation for the SQ64 is not great so I'm wondering if this is possible and I've just missed it. Anyone know?

(Btw, I know there are MIDI controllers out there that allow you to easily control their TX channel, but I'd prefer not to add any more equipment to my setup for now, mostly due to desk space reasons!)