A method of routing messages to multiple consumers comprises determining a probability function defining message classification probabilities for each of a plurality of consumer sets, receiving a plurality of messages, classifying each message, storing each message in a queue, receiving notification of a consumer available to process a message, ascertaining the consumer set to which the available consumer belongs, accessing the probabilities for the ascertained consumer set, selecting a message classification according to the accessed probabilities, and transmitting a message, of the selected classification, to the available consumer.