How to combine separate Zoom audio tracks into one file with dual mono tracks in FCPX?

I think I use FCPX in an eccentric way, so I'm not finding the answer even though I suspect it's quite simple.

I edit an audio-only podcast on FCPX. (It's what I know how to use.) So I have separate files for Person 1 and Person 2 from Zoom.

What I'd like is ONE file, in which Person 1 is on one mono track and Person 2 is on the other mono track of the same file. The reason I'd like it in one file is so that, as I edit a chunk out, it automatically comes out of both at the same time, so they stay in sync. But my attempts to create such a file instead make a file with two identical mono tracks, not one with Person 1 on one and Person 2 on the other.

How do I take my two Zoom tracks, and export them so that they are now one file with dual mono tracks? I found a few decade-old videos that teach me how to do that in, say, FCP7 or something even older, but I don't trust their advice for FCPX.

Thanks in advance and hope i have explained this clearly. It may be a weird way to do things, but it works for me when I have a track (from, say, Audio Hijack capturing Skype audio) that naturally comes in dual mono tracks.

[Re-Titled by Moderator]