(a) Determination of the unit shall be upon petition filed with the hearings official by the city or a labor organization.

(b) Within thirty (30) days after receiving such a petition and after notice to all interested parties, the hearings official shall conduct a hearing and receive evidence pertaining to the petition. Within thirty (30) days after the hearing, the hearings official shall designate the bargaining unit. In designating the unit, the hearings official shall take into consideration, along with other relevant factors, the organizational structure of the city government, the effect of over-fragmentation of bargaining units on efficient administration of government, the existence of a community of interest among city employees, including the similarity of duties, skills, interests and working conditions of the employees, the history and extent of city employee organization, and the recommendations of the parties involved.

(c) Subsections (a) and (b) above do not preclude the city and the labor organization from reaching a mutual agreement on designation of an appropriate bargaining unit. Such an agreement shall be filed with the hearings official and receipt of the agreement shall be confirmed and certified by the hearings official, providing no other affected labor organization or affected employee gives notice that his or her rights have been violated under this section. The hearings official may remand unit determinations to the affected parties before formally hearing or certifying such determinations if it is found that any affected party has not conferred in good faith or been given an opportunity to confer in good faith in an attempt to resolve the question prior to the request for formal hearing. Affected parties for the purposes of this subsection means the city, a bargaining agent, other affected labor organizations or affected city employees.