There's a book in Dutch literature, The Assault by Harry Mulisch. It's a great read if you're interested in multi-faceted morality. It deals with guilt and responsibility when there's a chain of things that need to happen for a bad outcome. During WWII the protagonist's parents are shot by Germans after a body of a collaborator was found in front of their house. The parents were arguing with the soldiers about someth…
A better heuristic, and almost as simple, is to rate responsibility in proportion to power, ie those with the most leverage to steer events take the most blame. Blame is information. It has no mass, and can be divided effortlessly.