Open-Xchange allows the administrator to configure (virtual) domains to receive emails. This is a supremely useful tool for organizations that house multiple franchises or divisions. 

For example, a company with locations in New York, Munich, and Amsterdam.  Administrators have the ability to create groups of employees for those locations.  Any mail that is sent to the central mail server is automatically routed to the server in the subsidiary, if they are used in a distributed mail server enviornment.  Similarly, a company with multiple spellings or abbreviated versions will remain a recognized whole with separate corporate identities.