A source computer 8 stores updated data that is to be distributed to a plurality of destination computers (12 to 30). The destination computers (12 to 30) are divided into groups sharing a common priority level (5, 4, 3, 2, 1). Each of these groups is then associated with a push update task to be executed by the source computer 8. These push update tasks are then sequentially executed. If a particular group of destination computers exceeds a threshold size, then it may be further divided in accordance with a hierarchy of splitting rules. The push update tasks use multicasting to transfer the update data to the destination computers within their groups in a manner that reduces network traffic.