Virtual machines in a network may be isolated by encrypting transmissions between the virtual machines with keys possessed only by an intended recipient. Within a network, the virtual machines may be logically organized into a number of community-of-interest (COI) groups. Each COI may use an encryption key to secure communications within the COI, such that only other virtual machines in the COI may decrypt the message. Remote devices may gain access to virtual machines in a network through a virtual device relay. The virtual device relay receives data from the remote device, such as a tablet or cellular phone, and forwards the data to one of the virtual machines, when the virtual device relay shares a COI with the destination virtual machine.