One way to give a breed priority to enter an event is to limit each level or stake to the specific breed during event setup.

If you plan to allow a specific breed to enter for a period of time and then open the event or level up to other breeds, you will need to manually change the allowed breeds for the event or each level/stake when it's time to open it up to the others.

Another way to handle this is to have all dogs immediately go to the waiting list (set level/stake or event limits to zero) and then manually allow specific dogs (the allowed breed) into the event. When it's time to allow other breeds, the event limits can be raised. At that time, as long as the waiting list has no queue, dogs will get into the event immediately.