There is a solution in .NET that will do this.  There was an article in MSDN 
magazine some time back about it.  The author was Oleg Tkachenko and you can 
find the article at:

http://msdn.microsoft.com/library/en-us/dnexxml/html/xml06162003.asp

Look here for alternative solutions:
http://www.experts-exchange.com/Web/Web_Languages/XML/Q_20858944.html

Xalan supports multiple outputs, as does EXSLT.  

Dimitre Novatchev wrote an interesting article on how to get MSXML to 
support EXSLT:

http://www.xml.com/pub/a/2003/08/06/exslt.html

Or, you can use one of the processors that are supporting XSLT 2.0...this 
feature is supported, but I have no idea when Microsoft will release a parser 
that supports it.

Regards,
Mike Sharp

"mike w." wrote:

> I have an XML file where I have this basic structure
> <sales>
>    <sale>
>        ....
>        <region>1</region>
>    </sale>
> </sales>
> 
> and I want to split off all the different regions into their own xml files.
> 
> how can I do this?
> 
> thanks
> 
> mike w.