[Zope] Script to automatically add "Member" role for first login using exUserFolder with SMB authentication

I setup my zope so that I can use the exUserFolder and login using my company's Windows Domain controller. I know how to manually add users so that they are part of the "Member" role but I want this to be done automatically the first time a user logs in to zope (or my plone site). How is this accomplished? I am very new to Zope and Plone but I am a long-time programmer - so please don't spare the details. :) Thanks, Jim Hodapp