Complex sentence: They have won a state-record total of 18 overall, while the boys' ice hockey team is very successful in the competitive NH Division I, where nearly all the other schools are much larger than Hanover.
Split into simpler sentences: They have won a state-record total of 18 overall. The Boys' Ice Hockey Team is very successful in the competitive NH Division I, where nearly all the other schools are much larger than Hanover.