The Verbit platform currently does not permit the same "exact" username to be shared across multiple accounts. When such is attempted, the admin adding the user on a second account will get an error saying: Email has already been taken and will not be allowed to proceed.

Example: Adding username@company.com to another account generates the error below.

In general, Exchange/MX servers ignore all characters preceded by the + symbol when routing emails.
i.e. username@company.com, username+1@company.com, and username+2@company.com shares the same mailbox which is username@company.com

Verbit users can exploit this Internet property to add the same username in multiple accounts and still virtually link the accounts to a single email address.

The user will need to log in using the exact username defined for secondary accounts.
In the above example, logging in using username@company.com will open the account Company1, and using username+1@company.com  will open account Company2.

Receiving emails 

When a job gets completed on Company 1, Company 2, or Company 3, the email notification from the accounts will be sent to the same mailbox, username@company.com

NOTE: Some Exchange servers can be configured to treat the + symbol as a valid character, making this trick fail.