(1) If more than one heir is appointed in such a way that they exclude intestate succession, and if one of the heirs ceases to be an heir before or after the date of the devolution of the inheritance, the share of the inheritance of that heir accrues to the other heirs in proportion to their shares of the inheritance. If some of the heirs are appointed to a joint share of the inheritance, the accrual is first effected between them.
(2) If the appointment of an heir disposes of only part of the inheritance and if intestate succession applies with regard to the remainder, then accrual takes place between the appointed heirs only to the extent that they are appointed to a joint share of the inheritance.
(3) The testator may exclude the accrual.