title: Manipulating collection from the inside
body: <p>I have a collection of panels which are highlighted when user clicks on them. I want to force them to behave as a set of radio buttons so only the one that is clicked on is highlighted and others aren't.</p>
  
  <p>I guess that there must be a way to manipulate whole collection (set property to false) from the inside, because the event is triggered by one item from the collection. Is there a way for the one item to manipulate whole collection? This is such a common feature in applications so I guess there must be a pattern how to do it properly. Thanks.</p>