I'm trying to make a page using data from the discogs.com (XML)-API. i've been parsing it with simpleXML and it's working pretty well but there is some things i'm not sure how to do.

Here is part of the XML:

<releases>
  <release id="1468764" status="Accepted" type="Main">
    <title>Versions</title>
    <format>12", EP</format>
    <label>Not On Label</label>
    <year>1999</year>
  </release>
  <release id="72246" status="Accepted" type="Main">
    <title>The M.O.F Blend</title>
    <format>LP</format>
    <label>Blenda Records</label>
    <year>2002</year>
  </release>
  <release id="890064" status="Accepted" type="Main">
    <title>The M.O.F Blend</title>
    <format>CD</format>
    <label>Blenda Records</label>
    <year>2002</year>
  </release>
  <release id="1563561" status="Accepted" type="TrackAppearance">
    <title>Ännu En Gång Vol. 3</title>
    <trackinfo>Backtrack</trackinfo>
    <format>Cass, Comp, Mix</format>
    <label>Hemmalaget</label>
    <year>2001</year>
  </release>
</releases>

What i want to achieve is something similair to how discogs presents the releases: http://www.discogs.com/artist/Mics+Of+Fury where diferent versions of the same release are sorted together. (see. The M.O.F Blend in my link) This is done on discogs with having a master release that features the other releases. unfortunately this information isn't present in the API data, so i want to do the same thing by grouping the <release>-nodes with the same <title>-tags, or add a flag to the <releases> that don't have a unique <title>? any good ideas on the best way of doing this?

i also like to know if it's possible to count the <release>-nodes (child of releases) that have the same type-attribute? like in this example count the releases with the type "Main"?

maybe it's better to do this things with XMLReader or XPath?