I think with our current file we are coming closer and closer to Figma's limits. It has already over 26k layers. We need to watch out that we don't get "locked out " of our own file soon, because it's too big to load.
I would suggest to place links to the groups individual files on the page of each group in our current file. These new files should still be editable by everybody so that everything is still open source and we don't loose the sense of an "atelier". We could also add a page (e.g. "Pausenraum") for exchange, fun and resources sharing...