I'm being asked to setup a mailing list for leaders of several similar companies which would have an email address domain different than the Zimbra server's currently hosted domain. Is it possible to have external email addresses as members of a Distribution Group in Zimbra? I noticed you can define which external addresses you want to allow to email the Distribution Group, but I have also read that a Zimbra Distribution Group won't distribute the emails to addresses outside of its domain. Is Zimbra+Mailman my only option here?
Running Zimbra 7.1