Split Property of Father with 2 wives.

Respected Sir/Madam, My father had 3 kids (2 boys & 1 girl) out of which 2 boys are from the first mother who died at young age, and the girls is from the second wife who he got married to post his first wife death, all 3 kids are married now. Now he owns a piece of land which is registered to his name post his first wife death. The second wife and her daughter are always cruel torturing us day in and out & our wives, and they are just here for money neither of them make a penny and uneducated but always blackmail my father and we 2 brothers they ask for property split and ask to write property to there name or else they would torture us everyday or file false complaints on us. After so many years of this torture and mental disturbance from such nuisance myself and my brother want to finally move away from them and go our own way for piece of mind. But now my father being alive and the torture from his second wife and her daughter how do we proceed ? My father his govt retired and earns some good pension, gets good rent from that property and we also as brothers paid very good money for family maintenance every month so he is self dependent. The amount of torture we have gone through from his second wife and her daughter we don't want them to enjoy all that property for which we have worked so hard and spend a lot on loans, monthly expense etc.. If we now want to split this property what is the best way to proceed ? Thanks Vijay