If it becomes evident in the course of a formal testacy proceeding that, though one or more instruments are entitled to be probated, the decedent's estate is or may be partially intestate, the court shall enter an order to that effect.
Order Of Partial Intestacy
Mont. Code Ann. § 72-3-315, under Formal Testacy and Appointment Proceedings.
Mont. Code Ann. § 72-3-315