Changing SimpleXML data within a loop

[eluser]anthrt[/eluser]
I'm doing some work with the Discogs API trying to serialize the data of a release for use in another local application.

A release on Discogs is something like a music album, so it contains the tracklisting, artists, remixers etc.

Here is a sample track row returned from the API, I'm using SimpleXML to parse the XML document.

Code:

<track>
  <artists>
    <artist>
      <name>Ramirez</name>
      <join>And</join>
    </artist>
    <artist>
      <name>Tajada</name>
    </artist>
  </artists>
  &lt;title&gt;Listen To The Drums&lt;/title&gt;
  <duration>8:10</duration>
</track>

Which more simply looks like this:
Ramirez And Tajada - Listen To The Drums

On this, I need to class the artist "Tajada" as a guest on this track, however, the "role" is defined in the previous artist's XML row:

Code:

<name>Ramirez</name>
<join>And</join>

How can I sort through the rows to 'swap' these around?

I can't figure out a way how to automatically detect the "join" in the previous artist element, and do some logic based on it within the next iteration of the loop.



I hope everyone can understand what i'm trying to get at, as I can't figure this out!
Regards