Two 1U Stereo Outputs connected to one Headphones module?

Hey all!

Would it be possible, or problematic in any way, to connect two 1U Stereo Output modules, ideally via 3-pin connector, to a single 1U Headphone module?

I am setting up a case for quadraphonic use, with one Stereo Output module feeding each of the pairs of jacks on the case, and I am looking for a way to monitor with headphones without missing everything going on in two of the channels. I can live without an accurate spatial image as long as I am hearing everything, albeit reduced to left and right positioning.

Any input would be appreciated!

The easiest would be to use a unity mixer for this I guess?

Yes you can do that with the 3pin connectors. 1st output module into input of 2nd output module. 2nd output into headphones input.