Multi-level grouping across multiple input files ques

First of all I want to know if this can be done.

below is a sample of over 3000 claim nodes in each of 6 documents.  Thats
over 18000 nodes to process.

The six docs are april.xml, may.xml...up to sep.xml.

I want to group by <vendorname>, then by the month of <actual>, then by
<loadnum>.

Is this possible using the document() function???

<claim claimable="no">
   <vendorcode>P0110</vendorcode>
   <vendorname>PINEAE GREEN HOUSE</vendorname>
   <vendorRollontime> 100 </vendorRollontime>
   <vendorontime> 100 </vendorontime>
   <cons> 105 </cons>
   <carrier>PINEAE GREENHOUSE</carrier>
   <carrierontime> 97 </carrierontime>
   <loadnum>215560</loadnum>
   <po>1653730</po>
   <due>5/7/2004 </due>
   <original>5/7/2004 8:45:00 AM </original>
   <scheduled>5/7/2004 8:45:00 AM </scheduled>
   <actual>5/7/2004 8:34:00 AM </actual>
   <vendstat>On Time</vendstat>
   <carrierstat>On Time</carrierstat>
   <buyer>???</buyer>
</claim>

-Kent Seegmiller