A famous example of this is Bletchley Park (an allied forces Second World War codebreaking centre where messages encrypted by the Enigma machine were decrypted) where people working in one hut would not know what the people in any other hut did.
A prominent example of this is Bletchley Park (a wartime codebreaking center run by allied forces during World War II where messages encrypted using the Enigma machine were deciphered).  In this instance, individuals working in one hut had no knowledge of what their colleagues in other huts were doing.