regarding my Right to the poperty

My father's grandfather wrote a will in 1965 about property he has. He shared the property to his wife, son, grandsons who are sons of his son. At last to the three daughter and to their sons alone( not to the grand daughter) . But that was based on a condition that they have right only to enjoy the amount got from that property. There is no freedom on selling those property. And also he wrote that if his daughter's son is having boy child , then that child can have full right over the property. And also he wrote if anyone not having male child, then the property will go his son's son(he even wrote the name to whom it has to go). My father being a son of his daughter have no male child. (Only 2 girl children). I,m upset that property will not neither come to me nor my sister because we both are girls. I think it not right that property is taken back since we are girls. Is there any way for us to get that property. Is that will can be taken as valid. I also heard it is ancestor property not the one who wrote this will