Khata bifurcation procedue in bangalore

I am living in an apartment which has around 120 units. Builder is yet to do Khata Bifurcation. My question is if the builder undertakes Khata Bifurcation, is it done for whole apartment or it can be done partially?

Example : Can he do Khata Bifurcation for only 90 flats and keep 30 flats untouched? If done so, for remaining 30 flats can he do bifurcation at later stage?