I'm using Zimbra for webmail for only a small number of users in my mail domain. I have my main mailserver copying email to the Zimbra server for these users. To do this, I had to create a subdomain for Zimbra to manage.
For the users that have access to webmail, I'd like their from: address to be the main email domain, not the subdomain that Zimbra is managing. Sofar, the only way I've found to do this is to add another domain to Zimbra and create an alias for the user.
However, the problem with doing this is that mail from one Zimbra user to another Zimbra user will be routed internally in Zimbra and never hit my main mailserver. The Zimbra users who check mail from the main mailserver won't see these mails until they use Zimbra.
Is there a good way to solve this problem?