I would guess a midi router could take the controller messages from
whatever channel and redirect them to another. I happen to have
qmidiroute, but I would imagine PD would allow even more control. There
are others as well that may be better. You should even be able to route
one control to one channel and another to a different one. This should add
little to your CPU usage as it is just looking for a byte stream and
changing one of them for the new channel.