The Generation-skipping Exemption
Another tax right we all have is a $1,010,000 generation-skipping tax exemption, which says that money that comes down to us from ancestors beyond our own parents can't be taxed up to a certain amount. When the adult children of the deceased already have a sizeable estate and don't need the inheritance provided in the will, they can use a disclaimer to pass that money down to the next generation without calling that exemption into consideration.
Since most estate documents on this level of wealth are pretty specific, this might be a case where you disclaim particular bequests, as laid out in the will. As long as the disclaimer is legally qualified and filed in a timely manner, it will be as though the deceased's children never inherited at all. That can have great tax benefits for all three generations.