As a comparison, I know Google Apps allows me to create email1@domain1 and email1@domain2 as a domain alias on the users.  This is the function I am looking for.  I basically have two domains and the email addresses are the same for each so I can use them interchangeably. 

I am one person using all of the emails so I dont want more than one user. From reading the forum, I can see that I would have to create filtered folders to organize all of these.

Thanks!