Hi Sriram,
Since this is a .unx and CR4Ent environment, probably there is a way out from the .unx end. Please post this to the Semantic space as well.
You would need to create a security table to hold the user_name,user_id and the campus_id at the database end and include this table in the universe schema.This table will 'join' with the 'dimension' table on user_id. A 'where' clause restriction like @variable('BOUSER')=user_name will have to be applied on the dimension table in order to fetch the necessary records per the user.
The 'BOUSER' i.e the list of BO users name has to match with the names stored in the security table.
Further, you could also create a cascading LOV at the .unx layer itself and restrict it based on the BOUSER so as to enable the required prompting for a 'district' user.
-Prathamesh
-Prathamesh