The definition of a PEMHCA-eligible employee under Cal. Gov. Code section 22772 (a) was expanded effective January 1, 2014 to include an individual who is both:  

A "full-time employee" of the state or a contracting agency within the meaning of Section 4980H of Title 26 of the United States Code and applicable United States Treasury Department regulations and interpretive guidance; and  

Designated in writing as an employee for purposes of this section by the state or the contracting agency, as applicable.  

A CalPERS Circular dated May 9, 2014 says that an employer may enroll ACA-eligible employees in PEMHCA health benefits by using a written designation by the employer.  This written designation is separate from the current agency resolution opting into PEMHCA health benefits.  Once an employer designates an employer as PEMHCA eligible, all other PEMHCA rules apply.  CalPERS will distribute additional guidance in the fall of 2014 regarding the enrollment process for this group of newly eligible individuals.  Alternately, employers may choose to offer coverage to this group of ACA-eligible individuals only outside of CalPERS to avoid assessable payments for failure to offer coverage.

The circular letter is available at http://www.calpers.ca.gov/eip-docs/employer/cir-ltrs/2014/600-019-14.pdf.