An employee working for two school districts must meet the 600-hour standard for each district. For example, if an employee works 400 hours per year for two districts under IMRF, the employee cannot participate with either district. If an employee is in a position requiring 800 hours for one district and 400 hours for another, he or she participates only through the first district. The only exception to this rule are school district treasurers (see 3.45 Other School Employees).