BlazeDS Point-To-Point messages

With BlazeDS on the server, we want to create a game in which clients can
play against each other, one on one. Now, we wonder how is the right way to
send Point-To-Point messages with BlazeDS. Subtopics means sending messages
to all clients, what, for me, seems not to be the right and scaleable way.
What is the best way for a "one-on-one" gaming system?