Since the majority of the staff want leave instead of cash, the company can schedule the staff's leave. Some big companies withe large number staff do schedule staff's leave so that staff will not take leave at the same time.
Anyway, Section 60E of the EA especially 60E(2) as reproduced below may be of interest to you:
"... (2) The employer shall grant and the employee shall take such leave not later than twelve months after the end of every twelve months continuous service and any employee who fails to take such leave at the end of such period shall thereupon cease to be entitled thereto:
Provided that an employee shall be entitled to payment in lieu of such annual leave if, at the request of his employer, he agrees in writing not to avail himself of any or all of his annual leave entitlement...."