[Zope] Redirecting based upone user

I have a list of users names in a MySQL table and I would like to write an index_html ZPT that sends the user to show_depots?depot=user/GetUsernName (ZPT) if they are in the MySQL list and show_countries (a different ZPT) if they are not. How should I go about this? Do I make index_html a Python script or ask them to login to a script /tracking/login maybe? Simon