Hide groups on e-newsletter subscribe widget based on user role

e-newsletter Subscribe widget will hide all non public groups to visitors, however when they submit their information to subscribe to the listed group it then shows all groups and is confusing to users.

We have it setup to sign them into the site as a subscriber as they register for newsletter.

Some of the groups are for internal use to be able to run test or identify certain members for special mailings.

We need to hide all non public groups to subscribers.