How to distribute property among brothers

I am hindu.my father had retired 3 year back and now my father is asking to divide the ancestor property between his 4 brothers , but his brothers are not dividing the property as they are saying first you divide your property between us which you bought 16 years back of your own income , then we will give you the share in ancestor property .If you will not divide your land between us , we r not going to give you your share in ancestor land.my grand father and mother died earliar and my father's elder brother and his wife had also died 7 years back .what should we do now to divide the property.