Related taxpayers shall include any corporations that are part of a unitary business under the Nebraska Revenue Act of 1967 but are not part of the same corporate taxpayer, any business entities that are not corporations but which would be a part of the unitary business if they were corporations, and any business entities if at least fifty percent of such entities are owned by the same persons or related taxpayers and family members as defined in the ownership attribution rules of the Internal Revenue Code of 1986, as amended.