Transposing Multiple Devices at the same time

Hey all, what is you best practice for live transposing of A4 and MM at the same time using a single keyboard. I would like to be able to press one note on the keyboard and they both transpose at the same time.

Cant figure it out for the life of me.

Thanks

To add to this. I am able to do this using a midi patchbay, but I would rather reduce the weight of my live kit and find a way to do it without it.