I am going to assume you are on Windows...
I haven't tried this myself, but one option might be to use Ghostscript with the Redirection Monitor:
Configure it NOT to prompt for file names. Now it should be acting as a Windows Print Queue that produces PDFs files.
So now you have your document in PDF format - the next step is to use a command-line tool that can split then rejoin PDF pages. Again, I haven't tried this, but perhaps you could use the pdftk burst command to split the file, then use the pdftk shuffle to reassemble the pages back into a single doc. You will need some sort of scripting, such as Windows Powershell or Windows Script Host to glue all this together...
This is all extremely kludgy, of course!!