How to Filter by CCK Select Field

I'm currently using the Relevant Content module to display blocks of related nodes of only one content type. The module is working great, except that I would like deeper control over it's filters. Right now I can only filter by content type. How would I go about filtering by content type, but then additionally filtering by a pre-created cck select field?

The select field is a checkbox site admins can select if the content is "Confidential." I have views set up that have access permissions set so that only logged-in, authenticated users can see the confidential nodes. Right now the Relevant Content module is pulling all the nodes (both confidential & nodes without the confidential select box checked) and displaying all the links even for anonymous users.

I don't want anonymous users to even know the Confidential nodes exist. This means I need to find a way to tell the Relevant Module block to only show nodes that are of a specific content type AND that are not marked as confidential.