How to dynamically change xslt page-sequence based on node attributes?

Question

The watered-down version of the problem I\'m having is this. For an XML file like:

Answer 1

Here is an XSLT 2.0 solution that uses xsl:for-each-group with group-adjacent:

Output:

   
      
         
      
      
         
         
      
      
         
      
      
         
      
   
   
      
         Item 1
         Item 2
         Item 3
         Item 4
         Item 5
         Item 6
         Item 7
         Item 8
         Item 9
      
   
   
      
         Item 10
      
   
   
      
         Item 11
         Item 12
         Item 13
         Item 14
         Item 15
         Item 16
         Item 17
         Item 18