buddy system
From Longman Dictionary of Contemporary Englishbuddy systemˈbuddy ˌsystem noun [countable] American English HELPa system in which two people in a group are put together to help each other or keep each other safeExamples from the Corpusbuddy system• And the kids have a buddy system they can count on.• They therefore blame not the buddy system but political patronage for government inefficiency.