I think you’d need a plugin, and if you were going to do that, you could likely just make a plugin that would do whatever you’re doing with Airtable (unless Airtable is the end, and not the means).
Have you tried creating a group_user_event and setting trigged_groups? There is no group attached to a user, so it’s not expected that groups would have any effect on the User, but UserGroups, that’s what you’re talking about. (I think.)