Splitting XML into multiple files with XSLT

I'm having a hard time wrapping my head around XSLT but I heard it's possible to split an XML file into multiple files. Basically I'd like to copy all the elements up to the first file and after the last file and then add the individual file content for each output file.

Could someone give me some pointers on this if it's even possible?

Thanks,

complete.xml

<rootelem>
  <elem>
    <file attr1='1'>
      <content>content file 1</content>
    </file>
    <file attr2='2'>
      <content>content file 2</content>
    </file>
    <file attr3='3'>
      <content>content file 3</content>
    </file>
  </elem>
</rootelem>

OUTPUT:

complete_PART1.xml

<rootelem>
  <elem>
     <file attr1='1'>
        <content>content file 1</content>
     </file>
  </elem>
</rootelem>

complete_PART2.xml

<rootelem>
  <elem>
    <file attr2='2'>
      <content>content file 2</content>
    </file>
  </elem>
</rootelem>

complete_PART3.xml

<rootelem>
  <elem>
     <file attr3='3'>
        <content>content file 3</content>
     </file>
  </elem>
</rootelem>