Selection Categories allow songs to be in two categories at the same time. In this demo, I'm making a Selection category and filling it with Rolling Stones songs. Then I can make a clock that will schedule Stones and nothing but Stones and then use that clock for an All-Stones hour on Saturday night. Selection categories don't have to be artist-specific, of course.They can be any grouping of songs that you choose. The songs in a Selection category will have totally separate, unique rotations from what the songs are getting within their regular Master categories.