XSLT Question - Split large XML into multiple smaller

I am an XSL/XSLT/XPath trying to break down very large well-formed XML 
files (as String messages) into smaller well-formed XML Strings using 
XSL/XSLT.

I am currently experimenting with Xalan - Java 2 from apache, but am 
having a difficult time finding examples that transform XML->XML and split 
it up.

Could someone help point me in the right direction?

Example: large.xml

<root>
   <level 1 (one to many)>
        <some children>
        <level 2 (one to many)>
            <some children>
            <level 3 (one to very many) >
                <some children /> 
            </level 3>
            <trailing siblings />
        </level 2>
        <trailing siblings />
    </level 1>
    <trailing siblings />
</root>
 

Level 3 is a unit of work.  Since JDOM is used to process the unit of 
work, we need to limit the size.  A new requirement has asked for 50MB 
batch messages containing..

several <level 1>
which may contain several <level 2>
which is likely to contain many, many <level3>

I would like to parameterize either by string size and/or unit of work 
count as to how the original XML is split.

Is this possible?

Thanks for any help.
-Paul 

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