1. A system comprising: a plurality of virtual machines, a number of the virtual machines adapted to receive multicast messages; and a computer system comprising: a virtualization engine adapted to provide an interface between the virtual machines and the computer system; a processor system operable, according to the virtualization engine, to process data for the virtual machines; and a network adapter adapted to: determine whether a multicast message has been received, the message including a destination address; examine a local filtering store for a match for the destination address; send the message to a number of the virtual machines if a match for the address is found; analyze a filtering store of at least one virtual machine for a match for the address if a match is not found in the local filtering store; send the message to a number of the virtual machines if a match for the address is found in a filtering store of a virtual machine; drop the message if a match for the destination address is not found in the local filtering store and the filtering stores of the virtual machines; and identify the virtual machines to analyze for a match for the destination address.