title: Check if IGrouping value contains result
body: <p>I have an IGrouping structure</p>
  
  <pre><code>IGrouping&lt;TierRequest,PingtreeNode&gt;
  </code></pre>
  
  <p>PingtreeNode contains a property of Response which in turn has a property Result.</p>
  
  <pre><code>    public class PingtreeNode
      {
          public ResponseAdapter Response { get; set;}
          // ... more properties
      }
  
      public class ResponseAdapter
      {
          public int Result { get; set; }
          // ... more properties
      }
  </code></pre>
  
  <p>What I want to do is check whether PingtreeNode contains any nodes with a Result == 2. I know the answer includes a SelectMany but I'm struggling to get the correct syntax.</p>
  
  <p>Anyone help?</p>