Membership - Single user for multiple application and different role in each application.

Hi
I have two .NET applications X and Y 
a. I want to have User A  as a common user for both application X and Y.
b. User A can have different roles on X and Y.  Eg. Read permission on Y and Write Permission on Y.
How do i configure ASP.NET membership to achieve about functionality.
Any Guidance and Directions.
Regards

 
 
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