Authenticating user on Web Page

Hi
I am using C# and Asp.Net to create web page. I want to give access to this page only to 2 to 3 people and others may be or may not be added to access the page based on future requirments.
I am trying to use the users windows login to give access to the page. But how can I give the access based on windows authentication only to the selected people.
Please let me know how can I do this. Thanks in advance.
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