i don't know how many collars you talking about but in my Va club we have a lot of dogs. My numbers are 5s 10-19. My buddy has 1s 0-14. Each dog man with the most dogs usually takes consecutive numbers to make it easy for everyone. We haven't had a problem yet until the other clubs hunt closer to us.
We normally have 80-100 dogs every saturday and there is 8 different dog clubs within 5 miles of us.