The scheduler receives a first message from one of the plurality of computer systems and registers the first message in a first queue. Then, the scheduler receives a second message from one of the plurality of computer systems. The second message has a logical dependency on the first message. The second message is registered in a second queue and in the first queue, wherein the queue entry of the second message in the first queue occurs after the queue entry of the first message in the first queue. The scheduler identifies the logical dependency of the second message on the first message by the order of the corresponding queue entries in the first queue and finally releases the first message for processing before releasing the second message according to the logical dependency.