If individual has a game at that time somewhere else remove their ability
If I have someone scheduled for a game do not allow me to double book someone. Remove their availability if they have a game already.

Unfortunately, we have decided not to incorporate this option. There are instances when officials wish to remain available for some organizations even if they already have a game. For this reason we leave it up to the official to decide how they wish to handle their calendars, but assignors are always made aware of potential conflicts via the conflict warnings systems in place that will fully provide schedulers with the details of their other assignments that may be a conflict.