Okla. Stat. tit. 58, § 58-1002: Beneficiaries

If property is so disposed of that the right of a beneficiary to

succeed to any interest therein is conditional upon his surviving

another person, and both persons die, and there is no sufficient

evidence to establish that the two have died otherwise than

simultaneously, the beneficiary shall be deemed not to have

survived. If there is no sufficient evidence to establish that two

or more beneficiaries have died otherwise than simultaneously and

property has been disposed of in such a way that at the time of

their death each of such beneficiaries would have been entitled to

the property if he had survived the others, the property shall be

divided into as many equal portions as there were such beneficiaries

and these portions shall be distributed respectively to those who

would have taken in the event that each of such beneficiaries had

survived.