I would like to relay a specific Exchange 2010 Mailbox to an external SMTP host, in this case Office 365, as we're migrating user by user to Office365. Meaning if the migrated users receives an e-mail, it should be automatically redirected to the defined host (Office365).
In Postfix this is really simply done by using the transport map /etc/postfix/transportmap:
Any ideas how this could be implemented using Exchange 2010? Exchange Transport Rules don't have any action available for this scenario.
Thank you in advance for your help!