Currently multimedia services for customers are rapidly being deployed (e.g. IPTV), and scalable multicasting is required for the needs of the services, e.g. robustness, security, and QoS. While native IP multicast is considered a good solution for the multimedia services, variety of overlay multicast mechanisms have been suggested to remove the barriers that block deployment of IP multicast on Internet. However, most of overlay multicast mechanisms do not consider host group model, which is not a problematic portion, but an advantageous feature of traditional IP multicast in terms of scalability, robustness, and security. In this paper, we propose a hybrid and hierarchical scheme to take advantages of both IP multicast and overlay multicast, based on host group model to gain performance efficiency for many group members on subnet dense mode. Overall network performance enhancement is shown in the performance analysis of our scheme, regarding low latency, small stress, and optimal stretch for multimedia receivers in subnet dense mode.