XSLT transformation to xml, grouping by key

Question

I have problem with write xsl to transform my xml to raport version. It looks like that:

    
        Jo         


        

Answer 1

This XSLT:

With this XML input:

    John
    Tom


    

        1001
        
    
    

        1002
        
    
    

        1001
        
    

Provides this needed result:

    
       John
       
          
Article1
          
Article3
       
    
    
       Tom
       
           
Article2
       
    

The further optimization might be using keys, but it looks premature with your structure.