Complex sentence: As cocktail parties became more high-end, the attire became subject to stricter guidelines, which allowed people to easily differentiate between the different identities at the party, the organizer, hostess, and wife.
Split into simpler sentences: As cocktail parties became more high-end, the attire became more strict. These strict guidelines allowed people to easily differentiate between the different identities at the party, the organizer, hostess, and wife.