One witness node may provide quorum witness functionality for multiple quorums concurrently (e.g., while multiple quorums are executing independently and simultaneously). An aggregated heartbeat message from a first quorum actor of the first quorum may include a first quorum heartbeat message that has a unique identifier for the first quorum. This identifier may allow update for the quorum data store with respect to the first quorum. The aggregated heartbeat message may also include information representing a second quorum heartbeat message from a second quorum actor of a second quorum. The second quorum heartbeat message may include a second unique identifier for the second quorum. The second identifier may allow an update for the quorum data store independently of the first update. More than two quorums may be supported by a single witness node by extracting individualized information from an aggregated heartbeat message.