Trying to remember which Vonnegut book I'm thinking of

There's a passage in a book which I *think* is by Kurt Vonnegut that talks about the minimum group of people to make a successful idea: Type A people are geniuses who have ideas; Type B people pick up ideas and can explain them; Type Cs have social weight to say "Listen to these people!". A successful idea requires each of types A, B and C. (It parallels some ideas in The Tipping Point, but I'm pretty sure this is a Vonnegut thing.) My question: In which book or story is this?