So, indeed, some of the groups have labels associated. Notably, the Developers group also confers “flair” to the avatar icons (see how mine has a Foreman logo on it). As such, this group is ask-to-join, while the others are open access.
Sadly I’m not sure I can come up with a good way to automate membership of that group - it is possible to write a whitelist of domains, and users with emai addresses matching one of those will be auto-added to the group - but in our case, that doesn’t really work. Many of our core people are not from the same domain, and still more choose to use their personal email anyway.
Fortunately, this is likely a one-time problem - once the majority of people who desire access to the Developer group have requested and got it, it should change relatively slowly. In addition, there are quite a few people who can grant access - the main issue I see is how to inform people that they should request access. Thoughts?