Round-robin

Round-robin is a document signed by multiple parties in a circle to make it more difficult to determine the order in which it was signed, thus preventing a ringleader from being identified

The term dates from the 17th-century French ruban rond (round ribbon) his described the practice of signatories to petitions against authority (usually Government officials petitioning the Crown) appending their names on a document in a non-hierarchical circle or ribbon pattern (and so disguising the order in which they have signed) so that none may be identified as a ringleader.

https://www.etymonline.com/word/round%20robin