A method, by an initiating entity (100, 200, 210, 220, 70, 75, 76), to initiate the set up of communication channels for exchange of information between the initiating entity and more than one responding entities (100, 200, 210, 220, 70, 75, 76), wherein the initiating entity and the more than one responding entities are located in an end-to-end control channel existing between a first entity and a second entity, the method comprising the steps of: - transmitting a first message of a Session Initiation Protocol on the end-to-end control channel between the first entity and the second entity, the first message comprising as a destination address the second entity address, wherein offer data is added to the transmitted first message, the offer data indicating that the initiating entity (100, 200, 210, 220, 70, 75, 76) is configured to support the communication channels and the offer data comprising an address at which the initiating entity is configured to receive the information, - receiving a second message of the Session Initiation Protocol on the end-to-end control channel, the second message comprising as destination address an address of the first entity, wherein the second message further comprises acceptance data in response to the offer data, the acceptance data indicating that a responding entity has accepted the set up of a communication channel and the acceptance data comprising an address at which the responding entity is configured to receive the information, - storing the address at which the responding entity is configured to receive the information, wherein the received second message further comprises acceptance data originating from the more than one responding entities (70, 75, 76, 200, 210, 220) located in the end-to-end control channel towards the second entity, the acceptance data originating from the more than one responding entities indicating that each of the more than one responding entities have accepted to set up dedicated communication channels between the initiating entity and each of the more than one responding entities, and the acceptance data comprising addresses at which each of the more than one responding entities is configured to receive the information, - storing the addresses of the more than one responding entities at the initiating entity in order to set up the dedicated communication channels between the initiating entity and each of the more than one responding entities. - transmitting a first message of a Session Initiation Protocol on the end-to-end control channel between the first entity and the second entity, the first message comprising as a destination address the second entity address, wherein offer data is added to the transmitted first message, the offer data indicating that the initiating entity (100, 200, 210, 220, 70, 75, 76) is configured to support the communication channels and the offer data comprising an address at which the initiating entity is configured to receive the information, - receiving a second message of the Session Initiation Protocol on the end-to-end control channel, the second message comprising as destination address an address of the first entity, wherein the second message further comprises acceptance data in response to the offer data, the acceptance data indicating that a responding entity has accepted the set up of a communication channel and the acceptance data comprising an address at which the responding entity is configured to receive the information, - storing the address at which the responding entity is configured to receive the information, wherein the received second message further comprises acceptance data originating from the more than one responding entities (70, 75, 76, 200, 210, 220) located in the end-to-end control channel towards the second entity, the acceptance data originating from the more than one responding entities indicating that each of the more than one responding entities have accepted to set up dedicated communication channels between the initiating entity and each of the more than one responding entities, and the acceptance data comprising addresses at which each of the more than one responding entities is configured to receive the information, - storing the addresses of the more than one responding entities at the initiating entity in order to set up the dedicated communication channels between the initiating entity and each of the more than one responding entities.