(a) “Retired participant activities” means one or more activities identified in subdivision (b), (c), or (d) of Section 22119.5 or (b), (c), or (d) of Section 26113 within the California public school system and performed by a participant retired for service under this part as one of the following:

1. (1) An employee of an employer.
2. (2) An employee of a third party, except as specified in subdivision (b).
3. (3) An independent contractor.

(b) The activities of an employee of a third party shall not be included in the definition of “retired participant activities” if all of the following conditions apply:

1. (1) The employee performs an assignment of 24 months or less.
2. (2) The third-party employer does not participate in a California public pension system.
3. (3) The activities performed by the individual are not normally performed by employees of an employer, as defined in Section 22131.