Allow creating aliases for new accounts in shared vaults. The alias should point to the owners mail of the shared vault, not the mail of the one creating the alias as this moves mails away from the origin account.

Example:
Part A shared a vault with Part B and assigns Part B admin rights.
Part B should now be able to create new logins in the vault and setup email aliases on behalf of Part A, so that mails stays within the same setup and wont spread to numbers of shared attendees.