title: How to implement one-to-one communication in MQTT?
body: <p>I am trying to set up a MQTT system for a project that connects many clients. </p>
  
  <p>These clients are of different type and may have different functionality. Some client-types have information - like temperature - which is being published but at the same time feature states that need to be set - like switches - which can be set by other clients.</p>
  
  <p>So using MQTT I came up with the following concept:</p>
  
  <ol>
  <li><p>The client publishes the informations it has - in the above example this would be the temperature, so like:</p>
  
  <p>customer/group/device/temperature</p></li>
  <li><p>When the client connects to a broker, in order to receive a state for the switch from different clients it subscribes to:</p>
  
  <p>customer/group/device/switch</p></li>
  </ol>
  
  <p>I have been using a websocket based solution so far but since MQTT is a famous protocol for IoT devices I was asking myself how to implement one to one communications between clients and came up with the above example of how I would do that. </p>