Build in some intelligence into the system that allows it to recognise user email domains and automatically apply permissions based on email domain e.g. all users registering with domain @abc.com can access Groups 1, 2 and 3; users registering with domain @def.com can access Groups 3, 4 and 5; and users registering with domain @ghi.com can access Groups 1, 3, 4 and 6. I'm aware that some of this functionality is/will become available via AD and future updates (HR feed), but this might be an added benefit for our building where we won't be able to add everyone using those tools as the building has mutliple separate tenants.