[xsl] breaking up XML on page break element

["Geert Bormans geert@xxxxxxxxxxxxxxxxxxx" <xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx>]

Hi all,

Here is a fun one I thought I could share

I have a nicely nested XML (a bit TEI like)
and markers for page breaks can happen everywhere in the document (as 
empty elements)

Now I want to break the document per page, reconstructing the structure
So in a first step, I want to isolate the pagebreak to the highest level

<book>
<title>...</title>
<section>
<para>aaa<pb/>bbb</para>
</section>
</book>

to become

<book>
<title>...</title>
<section>
<para>aaa</para>
</section>
<pb/>
<section>
<para>bbb</para>
</section>
</book>

Bearing in mind I need a generic solution
and pagebreaks can happen at every level

Any thoughts?
I am not looking for code, just curious on how people would attack this

Thanks

Geert