I have a customer that wants to send messages to a group of external email addresses like a LISTSERVER. They want to send an email with all the newest property listings each week to all broker agents on a distribution list. Their broker agents are not members of the orgainization. My thinkings is to use a distribution list open for anyone to join or leave automatically. But I am not sure how I would create the hyperlink or form the agent would use to request membership.
You can add external contacts (or mail users) to a distribution group, however someone will need to manage the membership. If you want to have the self management options, you will need to use code-based solution to handle group joining/leaving, there is no built-in option that you can leverage.