[Zope] Launching external apps to process uploads to LocalFS, possible?

I'm setting up a document repository that allows people to upload files (Using Zope) to a LocalFS directory. Those files then become visible through the Zope management interface. Is there any Zope friendly way to launch external Linux apps to process them once they have been uploaded? I'd like to translate .dvi and Word .doc files into PDF using wvWare and dvipdfm. I suppose I could use a cron job and a shell script to do the conversion at regular intervals, but I'd rather do it immediately. I guess what I am asking is if Zope's Python can be told to launch apps on the hosting machine.. But that seems like it would be a major security hole, so I understand if its not possible.. -Thank you, Chris