The present invention presents a flexible method for source-based message routing in a network node, particularly also suitable for flexible load distribution of the traffic via a number of link sets terminating directly at an adjacent first network element. The method uses data structures which are often already available in existing systems or are simple to set up, of providing a number of link sets between two signaling points. A two-stage routing process is initiated based on the setting up of a message node, which supports a number of logical networks or signaling point codes. In the first stage a logical network is selected, in which the message is to be routed further. In the second stage the message is routed in the selected network.