Authentication in web.config

Question

I'm writing a web page for a select number of users, using C#. I've used Windows authentication, and added the user ids into the allow users section of the web config.
However, I don't want to keep adding people to this everytime a new person joins the department or needs access.

I do keep a list of the users in a SQL 2000 table for other purposes, and I'd really like to be able to use this to allow any users from this table, but despite days of surfing, I'm no closer to an answer on how to do this.