Restrict to "Unsubscribe" only in Preference Center

Hey there, does anyone know of a way to allow users to only unsubscribe from segments inside the preference center? For example, I run a training course that people subscribe to. I do not want a random user to be able to subscribe to that course (represented by a mautic segment) in their preference center but once they are subscribed I would like them to be able to unsubscribe.

Anyone have a suggestion for how to do this?