A communication system includes multiple Point-of-Presence (POP) interfaces distributed in a Wide-Area Network (WAN), and one or more processors coupled to the POP interfaces. The processors are configured to assign to an initiator in the communication system a client Internet Protocol (IP) address, including embedding in the client IP address an affiliation of the initiator with a group of initiators, to assign to a responder in the communication system a service IP address, including embedding in the service IP address an affiliation of the service with a group of responders, and to route traffic between the initiator and the responder, over the WAN via one or more of the POP interfaces, in a stateless manner, based on the affiliation of the initiator and the affiliation of the service, as embedded in the client and service IP addresses.