2 folders 2 different Auth

I have a website with 3 areas. Public Side then 2 folders One Admin and One RegisteredUsers.

Everyone has access to the Public Side that's in the root of the website and every folder except the Admin or RegisteredUsers folders. Each of the folders has its own Login Form. Sot here is an Admin login form and a RegisteredUsers login form.

If someone authenticates into the RegisteredUsers area they can't access the Admin area and vice versa. Each one has different Authentication.

How would I accomplish that with the web.config files and the authentication process?

thanks in advance.

j