Land Property Issue

Hi Lawyer Jee, My grandfather had 40 acres of land which has been divided to my father and my fathers’ brother (Uncle) as per the values by that time by village gentle man’s (20.25 acres to My father and 19.75 acres to my father’s brother) and it is been partitioned to my father name and my uncles name and then to their children’s name (myself and my brother and my Cousins). Myself and my brother have 20.25 acres partitioned with passbook and my cousins have 19.75 acres with Passbooks. It was divided and partitioned in 1980’s. The land which we got by that time was value less and now it got becomes value than my cousin’s land. Now My Cousins are asking to re shuffle the land as it was my grandfather’s land and they are saying the similar rights on entire land else they would like to go to the court. Do still they have the rights on Partitioned land on myself and my brother’s? if they goes to the court, will the court accept the case as it was divided and registered 35 years back? if court accepts, how many years it may run the process? Please advise. Thanks.