In this chapter:
(1) "Participating employee" means an employee of a school district, other educational district whose employees are members of the Teacher Retirement System of Texas, participating charter school, or regional education service center who participates in a group health coverage plan provided by or through the district, school, or service center.
(2) "Participating charter school" means an open-enrollment charter school established under Subchapter D, Chapter 12, Education Code, that participates in the uniform group coverage program established under Chapter 1579.
(3) "Regional education service center" means a regional education service center established under Chapter 8, Education Code.