Complex sentence: Lewes and Georgetown were the first schools that decided to migrate from the Diamond State Conference and join and eventually every team from the Diamond State Conference (except for Middletown) joined the Henlopen Conference.
Split into simpler sentences: Lewes and Georgetown were the first schools that decided to migrate from the Diamond State Conference and join. Eventually every team from the Diamond State Conference (except for Middletown) joined the Henlopen Conference.