How to Add a Second Hosted Exchange Account to the Same Outlook Profile
To add a second Hosted Exchange account to your already used Outlook profile, open Outlook and click on file then Account Settings.
Click on New...
Let Outlook search for accounts for a while:
Then enter the new email address:
At this point, choose Exchange:
Then connect to the new account by choosing “more choices” and giving the new login name and password. Also tick in the "Remember my credentials" check box.
You’ll need to restart Outlook for the changes to take effect.