What is the correct Islamic legal action to take if two of the heirs refuse to divide agricultural land that the grandmother stipulated to be an endowment (waqf)?

A bequest in the form of an endowment (waqf) is valid, but it is limited to one-third of the estate. Any amount exceeding this one-third is contingent upon the heirs' approval. An endowment contingent upon death is considered a bequest in the form of an endowment, and the ruling concerning bequests applies to it, meaning it is limited to one-third of the estate. The heirs are obligated to execute the deceased's bequest within the limit of one-third of the estate. If the land does not exceed one-third of the estate, then all of it must be made an endowment. If it exceeds one-third, then an amount equivalent to one-third is endowed, and the heirs have the option to execute the remaining portion or refuse it. If the deceased had no estate other than the land, then one-third of it is made an endowment, and the remainder is divided among the heirs. It is not permissible for an heir to refuse to execute the bequest within the one-third limit.