With this script you can change each octave range to another octave range but you can also change the Midi channel as well.
A Midi channel set to zero means pass thru the original Midi channel.
If you assign a Midi channel number, the Midi channel coming in will get override by your Midi channel setting.
On my MiniLab Black keyboard, it's a 2 octave range. So in this picture I make. assignments to C2 and C3 to the Korg M1 with the instruments I have loaded in the M1.