What is the "main" backrooms group in universe? The one that controls the Backrooms Database? Most authors on this wiki would probably say that it was the MEG. However, I've really never liked having a "main group". When I write pages, I don't usually view them as being written by any group. Honestly, I tend to view my pages as OOC and not actually existing within the backrooms. If they do exist in-universe, then they're generic enough that they could've been made by any group. There are exceptions to this. My "Backrooms Guide" page is in-universe.
A lot of really great authors have been making pages that are meant to exist as in-universe documents. This brings up the issue of whether our whole wiki is meant to be an in-universe database or not. If it is a database, then that means that the group making the database would be the "main group" of our wiki. I personally have never been keen on the idea of having a single main group. I much prefer having many different groups, none of them being the "main" group on the wiki.