[xsl] XML overlap - processing a node-set defined by <start/> and <end/>

[Svante Schubert <svante.schubert@xxxxxxxxx>]

Imagine XML data, where continuous selection of data - randomly made by 
the user - is being marked by using a <start/> and <end/> element.

For example:

<ex:paragraph>
   <ex:START/>
   <ex:span>
       Some text C..
   <ex:span>
</ex:paragraph>
<ex:paragraph>
   Some text D..
   <ex:END/>
   <ex:span>
       Some text F..
   <ex:span>
</ex:paragraph>


The desired nodes would be
   <ex:span>
       Some text C..
   <ex:span>
   Some text D..

Is there an easy way to process this kind of selection with XSLT?

Best regards,
Svante