When a contact clicks on the "Unsubscribe" link, they are given the choice of unsubscribing from all lists or only specific lists that they select. If you need to make changes to the lists that appear on the unsubscribe page, you can do so by clicking "Manage Your Subsciption and Profile" that appears on the unsubscribe page.

Note: When a contact chooses to unsubscribe from all lists, this will include those lists that you have not made public.