Honestly, I'd rather you didn't. And I've got reasons for that, as follows:
These are not necessarily the Hand's Groups of Interest. This is, instead, the Library's. Now, that being said, if something is dangerous or interesting enough that the Library takes notice, then yes, they should be added. However, writing a handful of stories about something doesn't necessarily make them that interesting to the Librarian, Archivists, etc. Notice that The Factory and Wondertainment don't have analogues, nor do many, many other groups.
Additionally, I don't see this as a solid, be-all, end-all page. The notes at the top and bottom lay that out, I think. Instead, I'd rather people view this as a jumping off point. Fill in the gaps that I left, answer questions I left hanging (preferably different people with different answers), and above all else—Do not consider this canon.
Like all good documents for sites with flexible interpretation, you should be able to accept or discard all, some, or none of this page, at will. Head canon is a beautiful thing.
If you really, really, really want to add something, and you've gotten it all nice and ready, and you can explain why the library cares, then feel free to bug me in chat, through wikidot, or even in this very thread. But please don't add at will.