An Intelligent Transportation System (ITS) service station is provided that comprises a receiver configured to receive, from each of a set of ITS stations, a status message which includes the geographical position of the ITS station; a controller connected to the receiver and configured to determine, on the basis of the received geographical positions, whether a subset of ITS stations in the set meets a predetermined criterion of mutual proximity; and a transmitter connected to the controller and configured to transmit, when the subset comprises two or more ITS stations, a service message indicative of the subset to the ITS stations of the subset. Aspects may also include an ITS station receiving a service message.