The Board of School Trustees of the School City of Hobart hereby recognizes Service Employees International Union, Local 1-Division 208, as exclusive representative for custodial and maintenance bargaining unit retroactive to January 1, 1975, for the duration of this Agreement. The bargaining unit shall consist of all permanent full-time and part-time custodial and maintenance employees excluding any supervisor of custodial and maintenance employees, specifically the Head Maintenance Person and the Head Bus Mechanic. A “supervisor” means any individual who has (1) the authority, acting for the school corporation in the custodial and maintenance area, to hire, transfer, suspend, lay off, recall, promote, discharge, assign, reward or discipline school employees, or (2) responsibility to direct school employees and adjust their grievances, or (3) effectively to recommend the action set forth in these categories.