[Mailman-Users] disable unsub from a list?

Thanks for the info about preventing non-members from posting. I got it.

Because I currently have sendmail lists where users cannot unsubscribe (and are not allowed to), is there any mechanism for disabling a members's ability to do this? For example, a list to deliver emergency notices would not work too well if members were permitted to unsubscribe. At the same time, however, I desire the no-posting from non-members. Thanks.

Dave Robbins