in general those classes are an 
  easier interface for this achieving this functionality).
  
  <p>The StreamManager keep Streams in "groups" representing the type of Stream (for 
  example, Webcam, VOIP) with permissions settable on a per-group basis. By default, 
  only users with a publisher role and higher may publish a stream and users with a 
  viewer role and higher are able to subscribe.</p>
  
  <p> Most of the API's have a <code class="property">p_groupName</code> parameter that identifies the gr