How can I use loop in graphical message mapping

Question

The source input XML is like:
<bookstore>
  <book>
       <item1>xxx</item1>
       <item2>yyy</item2>
  </book>
  <book>
        <item1>zzz</item1>
       <item2>www</item2> 
</book>
</bookstore>
I want to create an output XML like
<output>
   <item>
        <item1>xxx</item1>
         <item2>yyy</item2>
    </item>
   <item>
        <item1>xxx</item1>
         <item2>www</item2>
    </item>
   <item>
        <item1>zzz</item1>
         <item2>www</item2>
    </item>
   <item>
        <item1>xxx</item1>
         <item2>yyy</item2>
    </item>
</output>
That means I want to do permutation and combination for all <item1> <item2> under <book>.
Of course I can write a customer function to do it, but I want to basically use the buildin functions to do the graphical message mapping for this.
Any idea?  thank you.

Answer 1

well, I'm not very clear of those 2 English words
What I want is to list all possible combination of item1 and item2 (and in fact, we have item3, item4, ....etc).
example
input: 
<item>
          <item1> 111 </item1>
          <item2> 222 </item2>
          <item3> 333 </item3>
</item>
<item>
          <item1> aaa </item1>
          <item2> bbb </item2>
          <item3> ccc </item3>
</item>
I want to get
<item><Item1>111>/item1> <item2>222</item2> <item3>333</item3> </item>
<item><Item1>111>/item1> <item2>222</item2> <item3>ccc</item3> </item>
<item><Item1>111>/item1> <item2>bbb</item2> <item3>333</item3> </item>
<item><Item1>111>/item1> <item2>bbb</item2> <item3>ccc</item3> </item>
<item><Item1>aaa>/item1> <item2>222</item2> <item3>333</item3> </item>
<item><Item1>aaa>/item1> <item2>222</item2> <item3>ccc</item3> </item>
<item><Item1>aaa>/item1> <item2>bbb</item2> <item3>333</item3> </item>
<item><Item1>aaa>/item1> <item2>bbb</item2> <item3>ccc</item3> </item>