naw, it goes by season standings..
if there is 20 teams, there is 4 brackets of 5.. the 1st, 2nd, 3rd, and 4th ranked teams are the top in each brackets. then 5th, 6th, 7th, and 8th fall under them. so one bracket would have 1st, 8th, 9th, 16th, 17th ranked team. then in prelims you play the four teams in your bracket. at least that is how race to 5 does it. im sure its pretty much the same for lower divisions