Housing co-operative

I am a member of Co-Op Housing society in Kolkata with eight members The building is having 8 flat(G+ 3) and each floor having two flats.Owner/members of the 2nd and 3rd Fr now propose to install one capsule type lift outside the main gate at the Gr Fr primarily at their own cost for the use of residents at these two Frs and marginally for residents of Gr.Fr and 1st Fr if at all.The proposed facility of a lift will mean additional construction (the encasement for the lift and installation of the lift) to the building, extensive civil work in one of the walls including shifting of windows and damage of the wall and encroachment of the common area at the Gr.Fr.This will also create management problem apart from financial cost of employing a lift man and electricity cost which the members of GRound and 1st Frs will not be ready to share.My question is :Is it permissible and can the Society's BOD allow this facility which clearly is intended to be used exclusively by the four members of 2nd and 3rd Frs and not for common use even though the project may be financed by those four members