Close request period before event

I’d like to be able to close my requests before the actual event begins. I work mostly with high schools and all of their song requests need to be vetted for lyrical content, so it’s be great to close the window before the event. I could make the event listing give the date I want to close requests, but then the kids get confused as to when the event actually is because they’re kids and are only barely paying attention :) Thanks for considering!