[Rudolf Bom]

Jeff, I am using the same box for 6 Video Sources and a Laptop for Stills etc. and combine this with a Behringer Audio Mixer X32 from which we take the L/R Signal over XLR. It works, but you have to set for all Video Sources the Audio Source to Analog (That is in the Audio/Video Setup), else you will keep listening to Audio from the Video Sources). Then further down in the Menu, you set the Audio CH to SD2 (when the XLR-Cables are on Audio IN 2), and then, you go one menu more down to Audio Fader, and set the Source to CP 12 PAIR – this sets the Faders 1/2 to Source 1 and the Faders 3/4 to Source 2 (That is Page 28 in the Manual).
This is how I got it working.
But: then I found out how to store Events and how to recall them, with the result that the programmed Events did not use the Audio Settings as previously programmed. Very annoying, so there is more to find out. If you are still working actively with this box (in itself it has a lot of capabilities compared to many other systems), we might get in closer contact to share experiences, the user-community for this box seems very small.
Best, Rudolf.