As the optimal use of network resources is a major issue for telecoms operators, we started works aiming to, firstly, improve the utilization of network resources by transmitting the IP packets in multicast when possible, secondly, to adapt the format of the data transmitted in multicast to take into account the context of the members of the multicast group, and thirdly to preserve the Quality of Service when a member of the multicast group moves from a radio network to another radio network. The paper shows, through a scenario, how our work will improve the utilization of the resources and then describes our approach.