Most juristic schools distribute shares to grandmothers on the father's side and grandmothers on the mother's side based on their generation level relative to each other. For example, if the heirs include a mother of mother and a mother of father of father, all four schools distribute a share to mother of mother only. On the other hand, if the heirs include a mother of mother of mother and a mother of father, Malik and Shafii distribute shares to both, while Abu-Haneefa and Ibn-Hanbal distribute a share to mother of father only.
Check the check box next to the grandmother who is of a more junior generation. If both are of the same generation make sure both check boxes are unchecked.