Default email domain for new users

[A Former User]

I was wondering if something like this was in the cards:

1. An admin can specify a domain to use for automatic mailbox creation for new users.
2. Users would be prompted to make a new email (if set when inviting this new user)
3. Users can see any mailboxes they have control over, and this same view provides customized instructions to add these emails on email apps per email