The should be entirely possible with the current cofiguration without any modification of the code. This would assume that you’d be using one unit/band as the input frequency and the other unit/band as the output band. This is what I would refer to as a “one-way” cross band setup. It would function much like a regular repeater…just on two bands instead of with a offset frequency within the same band.

You can also do this on a single port and treat it as a regular repeater within ORP. You would just need to make up a DB9 splitter cable from the Pi Repeater 2x port 1 that splits out to the two radios…1 as an input and the other as an output.

I have given this some thought before but have never gotten around to testing in the real world. It would be great because you could use a diplexer for filtering and using a single dual band antenna instead of using larger duplexer cans. It would make it more portable. Then you would just set up your dual band HT to transmit on the one band and receive on the other band…very similar to how you’d communicate with a satellite on two bands. Hope that gives you a good starting point.