I have a company that has an exchange server hosting their own domain, domain1.com. They were bought out by another company, and want to receive/send email under the new domain, domain2.com. The new domain, domain2.com, is not going to be hosted on this server, as the main server is at the company's headquarters. If I add the domain2.com as a host, they are unable to email anyone at HQ. How should I configure Exchange so that it accepts email for domain2.com and sends email out under the new default domain2.com smtp email addresses without it being considered a host?