A method for publishing a message includes receiving, at a first relay, a subscription request from a first client, wherein the subscription request includes a target. The method also includes: recording, at the first relay, subscription information of the first client based on the subscription request; receiving, at the first relay, a publication request from a second client, wherein the publication request includes a message string characterized by a pattern; determining, by the first relay, that the target matches at least a portion of the pattern; determining, by the first relay, if the publication request is a local publication request based on a predetermined policy rule; and transmitting the message string to the first client if the publication request is determined to be a local publication request.