My Great Grand Uncle's Children Are Not Allowing Me To Sell The Agriculture Land

My great grandfather was the 5th son to his father who had the self-acquired agriculture land & my grandfather is the only son to my great grandfather. Here, at my grandfather's level the total agriculture land was equally distributed among 5 son's children. from my grandfather, the property passed to my father. After my father's death, my mother got such land on her name. Like my father, my great grand uncle's children got their respective property on their names. Now, everyone got their respective land Patta passbooks on their names. However, we got the issue They are not allowing us to sell the property to outsiders. Pls help me how to proceed legally.