Bootrstap 3 - Liste Gruppe mit Akkordeon-Funktionalität

 <div class="list-group" id="menu">
 <a href="#" class="list-group-item" data-toggle="collapse" data-target="#sm" data-parent="#menu">MESSAGES <span class="label label-info">5</span> <span class="glyphicon glyphicon-envelope pull-right"></span></a>
 <div id="sm" class="sublinks collapse">
  <a class="list-group-item small"><span class="glyphicon glyphicon-chevron-right"></span> inbox</a>
  <a class="list-group-item small"><span class="glyphicon glyphicon-chevron-right"></span> sent</a>
 </div>
 <a href="#" class="list-group-item" data-toggle="collapse" data-target="#sl" data-parent="#menu">TASKS <span class="glyphicon glyphicon-tag pull-right"></span></a>
 <div id="sl" class="sublinks collapse">
  <a class="list-group-item small"><span class="glyphicon glyphicon-chevron-right"></span> saved tasks</a>
  <a class="list-group-item small"><span class="glyphicon glyphicon-chevron-right"></span> add new task</a>
 </div>
 <a href="#" class="list-group-item">ANOTHER LINK ...<span class="glyphicon glyphicon-stats pull-right"></span></a>
</div>

Trotz der beiden <a> bekam data-parent="#menu" keiner von Ihnen erscheinen auslöst, anderen zu verstecken. So aktualisieren Sie diesen code zu verstecken abgesucht andere sichtbar sind?