title: Ignoring nodes with duplicate data
body: <p>In the below xml, I would like to ignore the third node <code>&lt;Data1&gt;12347&lt;/Data1&gt;</code> because I have to account for only the first unique occurrence of <code>refCode</code>. Since the first node value and third node value of refCode is 112233, I want to ignore the third node.</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
  &lt;Example&gt;
      &lt;Row&gt;
          &lt;Data1&gt;12345&lt;/Data1&gt;
          &lt;Data2&gt;
              &lt;DataRef&gt;
                  &lt;RefName&gt;refCode&lt;/RefName&gt;
                  &lt;RefValue&gt;112233&lt;/RefValue&gt;
              &lt;/DataRef&gt;
              &lt;DataRef&gt;
                  &lt;RefName&gt;SKU&lt;/RefName&gt;
                  &lt;RefValue&gt;444-1112&lt;/RefValue&gt;
              &lt;/DataRef&gt;
          &lt;/Data2&gt;
      &lt;/Row&gt;
      &lt;Row&gt;
          &lt;Data1&gt;12346&lt;/Data1&gt;
          &lt;Data2&gt;
              &lt;DataRef&gt;
                  &lt;RefName&gt;refCode&lt;/RefName&gt;
                  &lt;RefValue&gt;325325&lt;/RefValue&gt;
              &lt;/DataRef&gt;          
              &lt;DataRef&gt;
                  &lt;RefName&gt;SKU&lt;/RefName&gt;
                  &lt;RefValue&gt;444-1113&lt;/RefValue&gt;
              &lt;/DataRef&gt;
          &lt;/Data2&gt;            
      &lt;/Row&gt;
      &lt;Row&gt;
          &lt;Data1&gt;12347&lt;/Data1&gt;
          &lt;Data2&gt;
              &lt;DataRef&gt;
                  &lt;RefName&gt;refCode&lt;/RefName&gt;
                  &lt;RefValue&gt;112233&lt;/RefValue&gt;
              &lt;/DataRef&gt;          
              &lt;DataRef&gt;
                  &lt;RefName&gt;SKU&lt;/RefName&gt;
                  &lt;RefValue&gt;444-1114&lt;/RefValue&gt;
              &lt;/DataRef&gt;
          &lt;/Data2&gt;            
      &lt;/Row&gt;  
  &lt;/Example&gt;
  </code></pre>