Within thirty days of the date written notice was given to affected employees that a valid recognition petition for an appropriate unit has been filed, any other employee organization may file a competing request to be formally acknowledged as the recognized employee organization of the employees in the same or in an overlapping unit (one which corresponds with respect to some but not all the classifications or positions set forth in the recognition petition being challenged), by filing a petition evidencing proof of employee support in the unit claimed to be appropriate of at least thirty percent and otherwise in the same form and manner as set forth in Section 2.52.040 of this chapter. If such challenging petition seeks establishment of an overlapping unit, the employee relations officer shall call for a hearing on such overlapping petitions for the purpose of ascertaining the more appropriate unit, at which time the petitioning employee organizations shall be heard. Thereafter, the employee relations officer shall determine the appropriate unit or units in accordance with the standards in Section 2.52.090 of this chapter. The petitioning employee organizations shall have fifteen days from the date of such unit determination or to appeal such determination pursuant to Section 2.52.110 of this chapter. (Ord. 377 § 5, 1980)