Wis. Stat. § 111.17

(1) In any situation where the provisions of this subchapter cannot be validly enforced the provisions of such other statutes or laws shall apply.

(2) All fringe benefits authorized or required to be provided by the University of Wisconsin Hospitals and Clinics Authority to its employees under ch. 40 shall be governed exclusively by ch. 40 , except that where any provision of ch. 40 specifically permits a collective bargaining agreement under this subchapter to govern the eligibility for or the application, cost or terms of a fringe benefit under ch. 40 , or provides that the eligibility for or the application, cost or terms of a fringe benefit under ch. 40 shall be governed by a collective bargaining agreement under this subchapter, a collective bargaining agreement may contain a provision so governing and such a provision supersedes any provision of ch. 40 with respect to the employees to whom the agreement applies. The employer is prohibited from engaging in collective bargaining concerning any matter governed exclusively by ch. 40 under this subsection.