(1) If the spouses have made dispositions in a joint will of which it is to be assumed that the disposition of one spouse would not have been made without the disposition of the other, the voidness or revocation of one of the dispositions results in the ineffectiveness of the other.
(2) Such a relationship of the dispositions to one another is, in case of doubt, to be presumed if the spouses mutually provide for each other in the will, or if one spouse makes a testamentary gift to the other and for the event of the survival of the beneficiary a disposition is made to the benefit of a person who is related to the other spouse or is close to them in another way.
(3) Dispositions other than appointments of heirs, legacies, testamentary burdens, and the selection of the laws of inheritance that are to be applied are not governed by subsection (1).