Land inheritance rights

Need advise. my mother is 82 years old. She along with myself and my 3 sisters (all married) are legal heirs of a land which was bought by my father. It is an unwritten agreement between all of us that post my mothers death, this land will be transferred to my possession and my sisters will have no right on the land. Kindly suggest what is the best possible means to make this effective without spending much on govt taxes and legal fees.