We consider the problem of multicast routing in a large single domain network with a very large number of multicast groups with small number of receivers. Such a case occurs, for example, when multicast addresses are statically allocated to mobile terminals, as a mechanism to manage Internet host mobility. For such networks, existing dense or sparse mode multicast routing algorithms do not scale well with the number of multicast groups. We propose an alternative solution called Distributed Core Multicast (DCM) that is based on an extension of the centre-based tree approach. We also describe how our approach can be used to support mobile terminals.