While network-level multicast has tremendous potential for increasing the efficiency of group-oriented applications, the adoption of network-level multicast has been tepid at best. In this paper, we propose a novel concept entitled stealth multicast that allows for practical adoption of network-level multicast on a domain-wise basis rather than global scale. In the stealth multicast model, similar unicast packets are dynamically assembled into virtual groups for multicast transmission across the domain. At the edge of the domain, the packets are converted back to unicast, thus hiding the existence of stealth multicast from the external Internet. True to its namesake, stealth multicast operates in complete stealth, providing seamless interoperability without requiring any modifications to end-user applications nor requiring any inter-domain support. In this paper, we introduce the basic concepts of stealth multicast and show that the stealth multicast model can offer significant benefit...