We're running a hosting solution with Zimbra and we're getting a little tired of manually adding aliases if a customer has more than one domain.
Is there any way to add "secondary" domains to the primary domains that Zimbra is using?

For example:
A customer has domain1.com with which Zimbra is configured, but then decides to buy another domain, domain2.com, and they want to have Zimbra configured so that e-mails sent to userx@domain2.com is delivered to userx@domain1.com, meaning that there should be aliases for domain2.com pointing to the "real" account, at domain1.com.
Can this be automated with Zimbra so that these aliases doesn't have to be created by hand?
Can a "secondary" domain be added to a customers already configured domain, so that Zimbra automatically creates the aliases?