Maybe I'm just not seeing the correct set of options, but here's the issue I'm dealing with:   A user wants to watch all of the "Arrowverse" shows, which include Arrow, Flash, Supergirl and Legends. At several points in those series, they overlap and cross-over. So the order in which the episodes should be watched is based on the premiere dates of episodes in ALL of these series, not just one of them. (It occurs to me that another historical example would Buffy and Angel...)   At first glanc