I have a breath controller and only want it on certain instruments in my setup.
If this is a dedicated MIDI Port, you can exclude this MIDI Port from the All MIDI Inputs in the Studio Setup. Then you can keep the All MIDI Inputs for other tracks, and select the dedicated MIDI In Port on that track, where do you want to use the Breath controller.
Or you can use MIDI Input Transformer on the tracks, to filter the Breath controller data out.
The former won’t work as this device does not have its own MIDI port
The latter won’t work because if I am filtering out the conflicting CCs, then I won’t be able to receive those CCs from other (desired) controllers.
Maybe you could have the breath controller and the VSTi’s you want it to control use a MIDI Channel that nothing else is using. That way the Tracks you don’t want to use the BC data will just ignore those messages.