Simple list -> Nested list based on attribute values

I have an XML document of the form

<doc>
  <item header='true'>Section 1</item>
  <item>Section 1.1</item>
  <item>Section 1.2</item>

  <item header='true'>Section 2</item>
  <item>Section 2.1</item>
  <item>Section 2.2</item>
</doc>

that I want to transform to the following:

<doc>
  <section title="Section 1">
    <item>Section 1.1</item>
    <item>Section 1.2</item>
  </section>

  <section title="Section 2">
    <item>Section 2.1</item>
    <item>Section 2.2</item>
  </section>
</doc>

I was able to match the @header <item>s with the rule 'item[@header =
"true"]' but couldn't work out a predicate to match "all subsequent
<item>s up until the next @header <item>".

Jason



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A-03-03-E