A communications protocol using group ordered message processing is disclosed. According to the protocol, a sending application groups messages together. The messages within the groups are then processed by a receiving application in the order received, but the groups themselves are processed in the order sent. More specifically, the invention pertains to a method for receiving messages at a processor node from another processor node via a plurality of communication paths. The method includes the steps of: receiving a message having a required number of messages value, comparing the required number of messages value with a number of processed messages, and determining whether the message is ready to be processed based on the result of the comparison. The invention can also be implemented as an apparatus. As an apparatus, the invention pertains to a processing node for a communication system which transmits messages between processing nodes interconnected by multiple communication paths. The invention has numerous applications, including transaction processing, parallel processors, distributed shared memory systems, asynchronous RPC mechanism, and bulk data transfer.