ancestoral property claimants and legal actions

My grand father who has got 2 daughters holds a share of ancestoral property and also there is another yet to be partitioned among his brothers and sisters. My grand father also had got married the 2nd time even when my grand mother was still alive. Grand fathers 2nd wife does not have any children. Now the situation is my grand father has already sold few properties without any consent of his daughters and plans to sell even more without getting his daughters consent. Pls advice us on what could be done so that the share of ancestoral property held by grand father gets tranferred to both his daughter's