folder based authorization in asp.net

Hello

 I have 3 folders in my ASP.NET 3.5 application main folder

MainFolder =  MyApplicationFolder     ( Having its web.config file )                                  

                Child Folder1 = EntryOperatorLevelFolder

                Child Folder2 = EntrySupervisionLevelFolder

                Child Folder3 =  SoftwareAdminLevelFolder 

Now i want that User of Child Folder1 should not be able to access any .aspx page in Child Folder2 and like that i ...