Hello - I have a similar need, although for a different use case -

I would like to run two instances of WSJT-X on the same machine (I expect this is another topic; initially I'd like to see if the two-audio-source problem is solvable), one taking audio from the left channel, one from the right channel. My application is to compare two separate receivers/antennas tuned to the same frequency. I do not see any option in WSJT-X (I am using version 2.2.2 on Windows 10 64-bit) to select from which "side" of audio WSJT-X accepts input audio for processing.

In searching the group, I've not immediately found a reference to separating two audio sources arriving on a stereo audio input device.

Thank you for any follow-up questions or advice.