Combinational networks provide simultaneous connectivity via networks of different network type between user equipment. For communication sessions on different network types, belonging to the same user equipment, a correlation check is enabled by introduction of an identifier denoted as Combinational Call Indicator (CCI). This CCI identifier in combination with the known Calling Line Identity (CLI) identifier enables user equipment and other and network entities to perform a correlation check between ongoing, or to be established, CScalls and PS-sessions. A user equipment, setting up a related communication session, sets the CCI identifier and provides the CCI identifier during the communication session setup towards the receiving user equipment or network entity, which is enabled to check whether the last received communication session is correlated to the earlier established session due to the presence of the CCI identifier.