Here's a similar, if weird, idea: "backup" stories. Just like how a lot of older comics would have a couple page story focused on another character, do that with the show. Each episode, you have 30 minutes of Arrow, and then 10 minutes of the backup "show". Maybe you'd have four "episodes" of a Diggle story, then three "episodes" of Black Canary, then a five episode Mr Terrific story. Etc.