Ancestral property given only to sons by Panchayati settlement.

My question maybe a little complicate and if anyone could provide me with case laws it would be helpful. a little background, My maternal grandfather passed away in 2008, at the time of passing he was involved in litigation regarding his share in the ancestral property of his father, while it was claimed by his 4 step brothers that he had been given up for adoption to his uncle. the property was obviously unpartitioned at that point. after my grandfather's death, his LR's became parties to the suit i.e. one son, widow of one son, two daughters, children of one pre-deceased daughter. Meanwhile, During the Pendency of the trial in the High Court the two sons entered into a panchayati settlement with the step-brothers of the Grandfather and accepted his share (presuming he was entitled to the share of his biological father). None of the other legal heirs were informed or present at this panchayat meeting. and neither did the two sons withdraw themselves from the ongoing litigation. The High court decided that my maternal grandfather was entitled to equal share in his biological father's property and the same was upheld later by the Supreme Court. After obtaining the Decree, the remaining legal heirs got mutation done according to the decree which was challenged by the opposite party before the SDM on the basis that the share of my maternal grandfather had already been given to his sons and the SDM agreed with this and cancelled the latter mutation made according to the orders of the High Court. an appeal was preferred to the collector and he held the same view. Now the question is what is the legality of this Panchayati settlement without the consent or even knowldege of other LR's and How should the other legal heirs approach this issue in order to obtain their rightful share in their father's property?