You want to send several midi channels from OT chromatic keyboard, and record to 1 midi track ? Not sure to get it.

With midi processors such Event Processor Plus, Midipal/Midibud/Midigal, Bomebox, RK002, you can send several channels from 1, by programing. IIRC it’s implemented in Midipal, easy to program in EPP, Bomebox…

Ah and with an Elektron Digi, I think you can do it (controlling several midi tracks with the same channel, sending different midi channels per track.