Hello Siraj,
Hope you are doih well. 
1. Hide these using KUT and assign the layout changes to the Business Role for which you want to assign.
2. Extension field can also be restricted in the definition of Business Role
(Off course this both options would be feasible if you have visibility controlled by Business Role. Example all fields editable for admin but only few editable for sales rep)
Is this what wanna accomplish? If no... can you also share on what criteria you want to hide.
Regards,
Chandan