my grandfather died in 1990 after his death the six acres land is on the name of their two sons my father and my elder uncle.my father have 4 sisters who all are now almost above 60 years old. and at that time all 4 sisters given no objection that the land will be on the name of two brothers only and they dont want anything. so since 1990 to till there are only two propertiers of that land my father and uncle and in this 21 years period none of there sisters objected about the land but now they are not allowing us to devide the land in 3 acres to each brother saying that those 4 are also the heirs of that property.
so I want to know that is it possible?those sisters have any legal authority to claim the property after 21 years?

