title: Add XElement to another XElement in specific location
body: <p>Please consider this <code>XML</code>:</p>
  
  <pre><code>&lt;Employees&gt;
      &lt;Person&gt;
          &lt;ID&gt;1000&lt;/ID&gt;
          &lt;Name&gt;Nima&lt;/Name&gt;
          &lt;LName&gt;Agha&lt;/LName&gt;
      &lt;/Person&gt;
      &lt;Person&gt;
          &lt;ID&gt;1002&lt;/ID&gt;
          &lt;Name&gt;Ligha&lt;/Name&gt;
          &lt;LName&gt;Ligha&lt;/LName&gt;
      &lt;/Person&gt;
      &lt;Person&gt;
          &lt;ID&gt;1003&lt;/ID&gt;
          &lt;Name&gt;Jigha&lt;/Name&gt;
          &lt;LName&gt;Jigha&lt;/LName&gt;
      &lt;/Person&gt;
  &lt;/Employees&gt;
  </code></pre>
  
  <p>That is content of a <code>XElement</code> variable.Now I have another <code>XElement</code> variable with this content:</p>
  
  <pre><code>&lt;Person&gt;
      &lt;ID&gt;1001&lt;/ID&gt;
      &lt;Name&gt;Aba&lt;/Name&gt;
      &lt;LName&gt;Aba&lt;/LName&gt;
  &lt;/Person&gt;
  </code></pre>
  
  <p>I want to add this <code>XEelemnt</code> variable to first <code>XElement</code> in a specific position (for example as second <code>Person</code> tag). How I can do this? </p>
  
  <p>thanks</p>