A system and method are provided for coordinating concurrent processing of messages communicated over a network. The messages include a pair of related messages having a common first unique identifier and an unrelated message having a second unique identifier different from the first unique identifier. A sequencer module determines which of the plurality of messages are the pair of related messages and which of the plurality of messages are the unrelated message. The sequencer module identifies a sequence order for the pair of related messages by determining a first position in the sequence order for a first message of the pair of related messages and a second position in the sequence order for a second message of the pair of related messages. The sequencer module inhibits the progression of processing of the second message until the first message is no longer pending while facilitating concurrent processing of the unrelated message.