Whenever an employee, for whose injury or death compensation is payable under this Article, shall at the time of the injury be in joint service of two or more employers subject to this Article, such employers shall contribute to the payment of such compensation in proportion to their wages liability to such employee; provided, however, that nothing in this section shall prevent any reasonable arrangement between such employers for a different distribution as between themselves of the ultimate burden of compensation.
N.C. Gen. Stat. § 97-51