Sorry I did not see this follow-up. Yes you can. In recent versions of xml_split, the -g or the -s options should give you what you need:

  -s <size>
       generates files of (approximately) <size>. The 
       content of each file is enclosed 
       in a new element ("xml_split::root"), so it’s 
       well-formed XML.  The size can be given in bytes,
       Kb, Mb or Gb.

   -g <nb>
       groups <nb> elements in a single file. The content
      of each file is enclosed in a new element 
     ("xml_split::root"), so it’s well-formed XML.