Filtering dynamic content: OR vs. AND

I'm working on a staff directory page for a client, using dynamic content. There are seven staff categories, and some staff belong to more than one category (e.g., "Administration" and "Leadership").

The data source is set up so that there is a separate column for each category and there are seven different filters for each category at the top of the page. Selecting multiple filters, however, decreases the results that are displayed rather than adding to the displayed results. For example, if I wanted to see everyone who was in Administration AND everyone who was in Leadership and I select both of those filters, I am actually seeing only those who are in BOTH of these categories. So I want the filters to function as "OR" rather than "AND."

I'm guessing there's a better way to do this... would love any insight anyone has!

Thanks!