Domain-based routes
Delivery routes based on domain groups are examined after defined user
directory-based routes for a match with an email message recipient. If a match is made with a user directory-based route, domain-based routes are not examined for matches.
Important: The Protected Domain group defined on the page should not be used to configure delivery routes if you need to define domain-based delivery routes via multiple SMTP servers. Create domain groups that contain subsets of the
Protected Domain group for mail routing purposes.