There is provided a method of signalling a message using a terminal address across multiple network entities. At least two contiguous network entities are associated with addressing spaces for which message addresses are not routable by way of the terminal address and are not otherwise routable by way of a single address. At every network border between any two contiguous network entities wherein an immediately succeeding network entity does not provide an addressing space through which the message is routable, it is determined whether the party number is to be stored and replaced with a new party number. If so, the party number is stored so as to permit its subsequent retrieval according to a last-in and first-out precedence to thereby create a stored party number. Once the party number has been stored, a replacement address is assigned as the party number. Also at every such border, it is determined whether the party number is to be discarded and replaced with a stored party number. If so, the last-in stored party number is assigned as the party number. The message is then routed according to the party number and, with the message, every stored party number is transported through the immediately succeeding intermediate network entity and through each further succeeding and contiguous intermediate network entity, if any, through which the message is routable.