Automate file upload

I'm looking for a way to have files uploaded with the upload module to be automatically over written with a newer version periodically. Has anyone seen something that will do this? Is there a name for this sort of thing that I can use to do some more research?

We currently have about 300 files which reside on our web server, but there are periodically updated master copies of each one located on our file server. I would like to set up drupal (or some other software) to automatically overwrite the files on the web server with the newer versions.

ideas anyone?

thanks!