(a) Employees of the Commission shall retain the right to:
(1) form, join, or assist an employee organization;
(2) bargain collectively through a representative that the employees have chosen;
(3) engage in other lawful concerted activities for the purpose of collective bargaining; or
(4) refrain from an activity described in this subsection.
(b) An employee may only present a grievance arising under a collective bargaining agreement to the Commission through the employee organization certified as the exclusive representative for the bargaining unit.