Email Center and User Addresses

Does anyone know if it is possible (and how) to put an eBS username in the To/CC/BCC fields of a message in email center and have the application retrieve the email address associated with the user record?

In other words, my eBS username is JS.  On my user record is my email address (john.smith@vaisala.com).  The user of the email center wants to be able to put 'JS' in the address field of a message and have the applicatioon send the message to john.smith@vaisala.com.

The business need is that we sometimes want a person who we don't grant access to email center to be aware of a particular communication.  Usernames are well known within the company, but the email address for "John Smith" isn't.  (It could be