SMTP Virtual Server to move mailboxes

Hello,

I need to move mailboxes between two domains. Right now there are 2 sites (1 for each domain using X.400 between them)in 1 Organization. I have installed the 1st E2K server into one of the sites and would now like to host all of the mailboxes on this server. Is there any way to do this without installing an E2K server into the other site/domain and then going to E2K native mode? Would setting up an SMTP virtual server on the existing E2K server for the other domain do this, or is this just for the purpose of hosting mail for another domain? Thank you very much!