Complex sentence: Parties involved in preservation include the 93rd Street Beautification Association and Carnegie Hill Neighbors who spurred the creation of the historic district; it is considered one of New York's most active community groups, seeking to preserve a village-like environment.
Split into simpler sentences: Parties involved in preservation include the 93rd Street Beautification Association and Carnegie Hill Neighbors. It was the latter that spurred the creation of the historic district; it is considered one of New York's most active community groups, seeking to preserve a village-like environment.