Not quite sure if this is possible with the core functionality of XenForo, or if there is an existing add-on that does this. But I have been looking at the "Banned email addresses" section of the users options, which almost does what I want, however I only want people with a few email domains to be able to register. For example, Say I own a company and all employees are given an email address from the company domain (or a couple of domains), I would only want those employees to be able to register using those email accounts. Another example is for students who have a school email address. I am looking to make a community for an existing set of people who all have the same couple of email types. However I would rather not have to add them all myself, for obvious reasons. Is this possible for the current system? Or is there an existing/ easy to make add-on?