template to group by tags

<?xml version="1.0" encoding="windows-1252"?>
<file xmlns="http://bibtexml.sf.net/">
    <entry id="art">
    <article>
      <author>Menindez, Isabel</author>
      <author>Perez, Juanito</author>
      <number>409</number>
    </article>
  </entry>
  <entry id="boo">
    <book>
      <author>Boyne, John</author>
      <editor>Gonzalez, Luis</editor>
      <editor>Gomez, Maria</editor>
      <year>2006</year>
    </book>
  </entry>
</file>

I need one templete 1.0 or 2.0 to group tags author and editor like
this, grouping the values by the word and:

<?xml version="1.0" encoding="windows-1252"?>
<file xmlns="http://bibtexml.sf.net/">
    <entry id="art">
    <article>
      <author>Menindez, Isabel and Perez, Juan</author>
      <number>409</number>
    </article>
  </entry>
  <entry id="boo">
    <book>
      <author>Boyne, John</author>
      <editor>Gonzalez, Luis and Gomez, Maria</editor>
      <year>2006</year>
    </book>
  </entry>
</file>