1. A method of queuing messages for communications between a first computer program and a second computer program, comprising the steps of placing a plurality of messages in a queue, wherein each message has a message body; placing selector information on each message, wherein said selector information contains information as to which message is to be processed next; and using said selector information on a message to identify a next message for processing, wherein a processor device executing one or more of said placing a plurality of messages, said placing selector information and said using.