(a) A privilege under Code Section 9-17-3 may be waived in a record if it is expressly waived by all mediation parties and:

(1) In the case of the privilege of a mediator, it is expressly waived by the mediator; and

(2) In the case of the privilege of a nonparty participant, it is expressly waived by the nonparty participant.

(b) A person that discloses or makes a representation about a mediation communication which prejudices another person in a proceeding is precluded from asserting a privilege under Code Section 9-17-3, but only to the extent necessary for the person prejudiced to respond to the representation or disclosure.

(c) A person that intentionally uses a mediation to plan, attempt to commit or commit a crime, or to conceal an ongoing crime or ongoing criminal activity is precluded from asserting a privilege under Code Section 9-17-3.