title: conditional XML, showing a tag only if the value exists for some other tag
body: <p>before I begin I must confess I am a newbie to XML. I have always consumed it without paying much thought that how they are created in the first place.
  So I have a XML document, now based on the value of few tags I need to wither show or hide its children. Do you know how I can do that. I have a feeling that XSL should bw able to handle that. 
  But I can test for the value of parent with XSL, but I am not sure how I will hide or show the children using the XSL.
  So for example in the below XML (this is how my template also looks like), I want to show the GlobalQHPCosts tag only if UseGlobalQHP is set to Yes. </p>
  
  <pre><code>&lt;UseGlobalQHP&gt;No&lt;/UseGlobalQHP&gt;
  &lt;GlobalQHPCosts&gt;
    &lt;Month&gt;January&lt;/Month&gt;
  &lt;QHPPrice/&gt;
  &lt;/GlobalQHPCosts&gt;
  </code></pre>