I'm looking for a free or reasonably-priced app or 3rd party mailing list service, like mailchimp, that offers features like:
subscribers/leaders (who cannot post)
contributors (who can post but with moderation)
Additionally, all subscribers are recipients of all emails, but "Leaders can be flagged as recipients of only leader emails.
Mailchimp, as far as I can tell, doesn't have the ability to have a subset of subscribers.
Anyone have experience with any of the services out there?