A method in a serving radio base station (310, 510, 720) of a first radio access network, serving a wireless radio device (390, 590, 790), comprising or initiating the steps of:—receiving a measurement report, wherein the measurement report is based on a reference signal received by the wireless radio device (390, 590, 790) from a radio base station (321, 521, 711) in a further radio access network;—sending an identification request referring to the radio base station (321, 521, 711) in the further radio access network to at least one neighbor radio base station (311, 312, 320, 330, 522, 512, 530, 721, 722, 730) of the serving radio base station (310, 510, 720);—establishing a neighbor relation using the information about the identification of the radio base station (321, 521, 711) in the further radio access network, based on received identification information.