Restrict Access To Category Page?

Hi There,

I can't seem to figure this out:

Background:

I have two user groups: Visitors (for strangers) and Members (for free user accounts).

All of my premium content (only available to free logged in users) is in posts that have the "VIP" category ticked during post creation.

I've added a negative rule for "Visitors (strangers)" blocking access to posts with the "VIP" post category.

I've added a positive rule for "Members" who are logged in to allow them to see post categories that are "VIP". All good.

When Visitor strangers try to access INDIVIDUAL posts that are "VIP" categorized, they get the correct "Please login" protected content page. All good.

Problem:

In my site nav Wordpress menu bar I have a menu item that is simply a link to the /vip/ category index page. This page is NOT displaying the "protected content please login to view" warning, it just says "Sorry, no posts matched your criteria.". How can I add this /vip/ page itself as a protected area? I tried adding http://www.domainname.com/vip to the URL groups feature, but that didn't seem to work.