I would assign the 5-8 channels to the midi out (RD2000)
And then midi them to the midi in for left right1, right2, right3
Set the chord detection to the same as the left hand..
And then you can mix and match you RD2000 sounds on 1-4 with the Genos sounds..
Just use plain midi in and out..
Midi in, because you want thte Genos to be midi master clock