Hi Faheem,
Create a roles for User and add queries in role's menu. Add authorization object S_RS_FOLD in role to disable infoarea field in BEx.
Along with this add authorization object S_RFC, S_RS_COMP , S_RS_COMP1 and S_RS_AUTH(add proper analysis authorization) which provide authorization to users to execute the query.
With this setup of authorization, when user will login in BEx he/she will be able to search only those query which is added in roles menu and assigned to him/her.
Thanks-
Guru