authorization in web.config

hi,
I have the default permission like this.. 
   <authentication mode="Windows"/>
    <identity impersonate="true"/>
    <authorization>
      <allow users="Ad\qasrv, Ad\user1, Ad\user2"/>
      <deny users="*"/>   
    </authorization>
 ...............
then the special page will have the following permission. 
<location path="specialpage.aspx">
    <system.web>
     <authorization>
      <allow users="Ad\user2, Ad\user3"/>
      <deny users="*"/>
     </authorization>
&nbs ...