How to filter set of requirements by category?

I have a set of requirements that includes three item types: text, folders, and requirements. I have properly classified the items into one of two or both categories. I would like to filter and export the items from that set that fall within one of those categories. How do I do that? Can it be done with tags? The filter doesn't seem to have an option to filter within the set and the set filter doesn't have a categories/tags option.