For better accountability and security for the Customer, only set up external Users who have a direct e-mail address. Do not set up individuals that are part of an e-mail group that multiple Customer Users can access.
Final Mile Track is an eCommerce site where orders are placed, and the Customer is financially responsible. Using a direct email address allows the Customer to know exactly who placed each order and limits the liability if a Customer disputes an order placed by a User.
If a Customer’s User is terminated, he/she can remove the terminated User without affecting other Users that use Final Mile Track.