Subject to the review and approval of the attorney general, an agency may adopt a written policy that, in addition to the requirements of this chapter, limits the extent to which a public officer in the agency or an administrative unit of the agency may
(1) acquire a personal interest in an organization or a financial interest in a business or undertaking that may benefit from official action taken or withheld by the agency or unit;
(2) have a personal or financial interest in a state grant, contract, lease, or loan administered by the agency or unit; or
(3) accept a gift.