Suppose I have 3 kinds of users and their accessible pages in my ASP.net application are as follows:
(1) User Type-A {Default.aspx, a.aspx, b.aspx and c.aspx},
Role management in asp.net may help you in this case. Please check this article. You may have to customize this as per your specific requirement. Hope this helps.
Role Manager in ASP.NET
Each of User-Type will be associated with Roles.