MIGX: How to show items from a drop down list

So I’m working on a resource center and one of my MIGX fields is a listbox of categories:

  • Podcasts
  • Presentations
  • Documents

These are applied to each item in the TV. But sometimes some of the categories are not used. I’d like to show all of the currently used categories, as taken from the list of resources, as their own list that I can use for the Resource Center’s tabs. It would look something like this Resource Center Concept.

So using the example above, suppose that Presentations weren’t used as a category, I’d like to make it so that the tab and it’s content would not generate.

Alternatively, I guess I could make a secondary TV that also contains the same categories as a series of checkboxes that the user could select as which ones to show content for. But I’m curious if this can be done using the one MIGX TV?

Thank you for any ideas.

Can you name a case when they are not used?