Abstract: A system for dynamically partitioning processors in a multiprocessor system intercoupled by a network utilizes, in association with each processor, a network accessible, locally changeable memory section. An available one of a number of common dynamic group addresses in each of the memories is reserved for a subgroup for the performance of subtasks within an overall task, and members of the group are designated as they receive messages to be processed. The members then locally update status words which establish membership, group validity and semaphore conditions, so that transactions may be initiated, coordinated and terminated with minimum involvement of processors that have no relevant subtasks. When the full task is completed the dynamic group is relinquished for use when a new task is to be undertaken. The system enables many tasks to be carried out concurrently with higher intercommunication efficiency.