Adding an additional exchange server to the same ORG W2K3

Is it possible to add a 2nd exchange server to the same administrative group and split the mail boxes between them? If so, what is the correct method to set it up. I currrently have a primary exchange server and I setup a secondary server and moved a few mail boxes. The moved users can send mail but cannot receive. The mail just sits in the SMTP queue on the primary server waiting to be delivered. Any ideas?