The present invention addresses the management of user groups, user contact lists, and user access lists in a telecom-communication system whereby a user access to a group and list management server for creating, deleting or modifying a group, contact list and access list in terms of group policies and members. User groups, user contact lists, and user access lists are operated without any validation other than being syntactically correct, and without taking into consideration the users access capabilities, the users privacy, and even the user existence. In particular, the telecommunication system may comprise a number of networks operated by different network operators where the users hold subscriptions. The present invention offers a new interface between a group management server and a subscriber server of a network operator where the users hold their subscriptions, so that user policies in the subscriber server govern operations on groups, contact lists and access lists.