how to make a particular url of set of urls present in folder not accessible even though the user belongs to the role have access to the urls

Hi All,
I have 3 roles namly Admin ,Employee and Customer.
I have created three folders namely Admin,Employee and Customer and created access rules in the respecitive folders and placed all the urls in the sitemap  and the sitemap has been placed in the root folder of the application
In Admin Folder i have the following URLS
AddUser.aspx
RemoveUser.aspx
ModifyUser.aspx
Manager.aspx
In Admin Folder
<configuration xmlns="http://schemas.microsoft.com/.NetConfiguration/v2.0">     <system.web>         <authorization>             <allow roles="Admin" />            ...