Some years ago I asked a lawyer about this. As I recall, your brothers and sisters have no claim IF you have a will that leaves the property to someone else. Property goes to your spouse if you have one and to your children, equally divided. If you have no spouse or children, it goes to your parents. You are not forced to leave your estate to your siblings if you have a will. Anyone, by the way, can leave 20% to whomever or whatever they want. I urge you to see a lawyer, who deals with inheritance issues, not to any lawyer who may have limited knowledge of the topic -- and get good recommendations for a lawyer because lawyers in Argentina are desperate for work and will tell you they know the topic when they may not.