(a) A will is valid as regards form, irrespective particularly of the place where the will has been made, the location of the assets, and the nationality, domicile, or residence of the testator, if the will is made in the form of an international will complying with the requirements of this subtitle.
(b) The invalidity of a will as an international will does not affect its formal validity as a will of another kind.
(c) This subtitle does not apply to any form of testamentary disposition made by two or more persons in one instrument.