The way I picture this is by letting communities have some sort of "partner communities" listing. If mods of games@xyz decide they like the content of games@abc, and gaming@123, they add those communities as "partners" (perhaps those communities have to accept which in turn adds games@abc as their partner). Then, when any user subscribes to one partnered community, they also become subscribed by proxy to the others, and begin to see posts from all 3.
This helps smaller communities piggyback on the success of willing larger communities and gain a bit of visibility as well, which should encourage growth of each partner so smaller ones don't just die out.
Communities can "unpartner" at any time, in which case users would only remain subscribed to the one they originally selected. And of course, users could explicitly block any of the partnered communities if they don't want to see the whole set.
How does this Dev Team interact with the official Lemmy repository? Based on the Reddit post where you were directing people to message the Mod team rather than visit the Lemmy GitHub page, somehow I get the impression you guys are working on a forked version of Lemmy rather than contributing to the core repository. Is that accurate?