Do you think it is possible, in a novel, to use multiple first person perspectives (each perspective having a set of scenes) in which there is no obvious distinguishing mark other than voice? For example, Scene 1 is from one character's perspective. We know that scene 2 is from another character's first person perspective because the voice has changed. We know that scene 3 is from the first character's perspective because the voice is the same as Scene 1. I'm toying with this idea, but I don't know if it would work.