When you have some users on our Hosted Exchange and some users on our POP3 servers, you need to make sure that you add all users on the Hosted Exchange to the POP3 server with the same username. Then, you will need to go to the Mail tab and select the Redirect All Mail to option. In the text box below that option, enter the alternate email address for that user.
Alternate E-mail Addresses:
Every user has an alternate e-mail address in the format of:
Example: If you have a user account named jdoe hosted for domain company.corp on the exg7.exghost.com server, then this user account would have an e-mail address of firstname.lastname@example.org and an alternate e-mail address of the following:
Current alternate domain name is:
Select the Preserve To/Cc fields option. This makes sure that a POP3 user puts multiple Hosted Exchange users in the To field or the Cc field, that it will display correctly and not cause confusion.