Embodiments of the invention relate to method of, and system for, controlling access to a plurality of communications sessions involving a plurality of users. In a method according to an embodiment of the invention each of the communications sessions is for access by a plurality of users and data identifying said plurality of communications sessions have been stored in association with data indicative of one or more associated characteristics. The method comprises: receiving a request (M1) to initiate communications among members (T1, T2, T3, T4) of a group of users, said request comprising data identifying the group of users; responsive to receiving said request, selecting a communications session on the basis of data identifying the group and at least some of said stored data indicative of characteristics of a given communications session; and transmitting messages to at least some members of the group, the or each message (M2a, M2b, M2c) having a message body comprising data providing access to the selected communications session and a destination address determined from data indicative of a given member of the group.