I need group by tags this xml for example. The problem is that I dont
know the name of the tags. Only I know the tag "Book" and the ID "boo2"

<?xml version="1.0"?>
<rdf:RDF   xmlns:foaf="http://xmlns.com/foaf/0.1/"
    xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">

<Book rdf:ID="boo2">
   <address rdf:dataytpe="aaa">Almogavers 56</address>

   <event>
      <Inbook>
         <month rdf:dataytpe="bbb">July</month>
      </Inbook>
   </event>
   <event>
      <Inbook>
         <year rdf:dataytpe="ccc">2006</year>
      </Inbook>
   </event>

   <proceedings>
      <Proceedings>
        <year rdf:dataytpe="ddd">2008</year>
      <Proceedings>
   <proceedings>

<?xml version="1.0"?>
<rdf:RDF   xmlns:foaf="http://xmlns.com/foaf/0.1/"
    xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">
<Book rdf:ID="boo2">
   <address rdf:dataytpe="aaa">Almogavers 56</address>

   <event>
      <Inbook>
         <month rdf:dataytpe="bbb">July</month>
         <year rdf:dataytpe="ccc">2006</year>
      </Inbook>
   </event>

   <proceedings>
      <Proceedings>
        <year rdf:dataytpe="ddd">2008</year>
      <Proceedings>
   <proceedings>