California Code, Health and Safety Code - HSC § 1373.5

When spouses are both employed as employees, and both have enrolled themselves and their eligible family members under a group health care service plan provided by their respective employers, and each spouse is covered as an employee under the terms of the same master contract, each spouse may claim on his or her behalf, or on behalf of his or her enrolled dependents, the combined maximum contractual benefits to which an employee is entitled under the terms of the master contract, not to exceed in the aggregate 100 percent of the charge for the covered expense or service.

This section shall apply to every group plan entered into, delivered, amended, or renewed in this state on or after January 1, 1978.