It is possible with ResDiary to close-out your entire restaurant for individual time-slots. You can close-out as many individual time-slots as required.
Once a close-out is in place no new bookings can begin during that time period. Bookings which begin before the close-out can still overlap with the closed time.
Go to the date in the diary you wish to add a close-out time for. Select the "Close-out Management Console" in the top right hand corner of the main diary page