Technically feasible. But this will open up Pandora's box. People will be able to know how less number of seats are available for GN quota. Nonetheless, if this feature is provided, then it would be helpful for lot. For example a differently abled person might like to choose a berth near the door. I might would like to choose a berth at the rear end of AC II tier, where there are only 2 berths available and feels like a coupe.