A method of implementing policy management in an IP Multimedia Subsystem, IMS, the method comprising the steps of: adding a user as a member of a group, the group being defined by a Group Document that is managed by a XML Document Management Server, XDMS, that identifies the members of the group and includes policies that are applicable to the group, wherein the policies included in the Group Document comprise a maximum number of sessions in which members of the group are allowed to participate simultaneously; maintaining, in the XDMS, dynamic data relating to the group members in the Group Document, wherein the dynamic data comprises the number of sessions in which members of the group are participating; and retrieving the dynamic data included in the Group Document, by an Application Server, AS, from the XDMS, and taking into account the dynamic data included in the Group Document when making a policy decision that is to be applied to the user, including: determining, by the AS, if the number of sessions in which members of the group are participating is less than the maximum number in which members of the group are allowed to participate, and if so, then determining, by the AS, that the user is allowed to participate in a further session and updating, by the XDMS, the number of sessions in which members of the group are participating, and if not, then determining, by the AS, that the user is not allowed to participate in a further session. adding a user as a member of a group, the group being defined by a Group Document that is managed by a XML Document Management Server, XDMS, that identifies the members of the group and includes policies that are applicable to the group, wherein the policies included in the Group Document comprise a maximum number of sessions in which members of the group are allowed to participate simultaneously; maintaining, in the XDMS, dynamic data relating to the group members in the Group Document, wherein the dynamic data comprises the number of sessions in which members of the group are participating; and retrieving the dynamic data included in the Group Document, by an Application Server, AS, from the XDMS, and taking into account the dynamic data included in the Group Document when making a policy decision that is to be applied to the user, including: determining, by the AS, if the number of sessions in which members of the group are participating is less than the maximum number in which members of the group are allowed to participate, and if so, then determining, by the AS, that the user is allowed to participate in a further session and updating, by the XDMS, the number of sessions in which members of the group are participating, and if not, then determining, by the AS, that the user is not allowed to participate in a further session. determining, by the AS, if the number of sessions in which members of the group are participating is less than the maximum number in which members of the group are allowed to participate, and if so, then determining, by the AS, that the user is allowed to participate in a further session and updating, by the XDMS, the number of sessions in which members of the group are participating, and if not, then determining, by the AS, that the user is not allowed to participate in a further session.