Simplify restricting content through tags

I've released a new module and set up page visibility so that purchasers can only see this content. However, I see now that they can use the Search bar and see everything. I'm now going through and tagging all of my content (very labor intensive). But it would be nice to be able to say Audience members with this tag can only view content with this tag (requires one piece of content to be tagged in order for permissions to be correct) rather than every piece of content to be tagged in order for permissions to be correct.