code: public void add(final String[] pl) throws DevFailed {
  	synchronized (this) {
  	    for (final String element : pl) {
  		if (element != null) {
  		    final Vector v = factory.instanciate(element);
  		    final Iterator it = v.iterator();
  		    while (it.hasNext()) {
  			add_i((GroupElement) it.next());
  		    }
  		}
  	    }
  	}
      }
docs: Adds devices matching patterns <pl> to the group
  
  @throws DevFailed