Abstract: Order associated with messages is preserved in an environment wherein a message includes an associated order identifier; a receiver is operable to receive a first message associated with a first order identifier and a selection component is operable to select a first entity for processing the first message. The system includes a determination component for determining whether a notification associated with completion of processing of the first message has been received by the receiver; and a controller for controlling the selection component to select a second entity for processing the second message, in response to a combination of receipt of the notification and a second message associated with the first identifier being received by the receiver preceding the receipt of the notification.