Systems and methods to organize the flow and processing of queued messages may: receive messages in a set of processing queues; select a first and second processing queue; select a first and second message in the first and second processing queue; process the concurrent portions of the first and second message simultaneously; select a third processing queue and determine a subset of messages that are its oldest messages; assign a first sequential numbering to the messages in the subset; assign a second sequential numbering to those messages in the subset having a concurrent portion that has been previously processed and a sequential portion that has not been previously processed; determine whether the oldest message in the subset was assigned the same number in the first sequential numbering and the second sequential numbering, and, if so, process the sequential portion of the oldest message.