I'm pretty sure that track seeds individual events--giving preferential lane and heat assignments to the best times and field event marks. I'm pretty sure swimming does this, too. I don't think there's any way to seed teams, just individuals.
For sectionals, there used to be qualifying marks way back in the old days, but for the last 30 years or so, I believe schools have been allotted 2 individuals per event and 1 relay team, unless they had 3 or more individuals meet the state meet qualifying standard.