Complex sentence: She immediately invited them to one of her parties at her New York penthouse, where the two guitarists performed in private for the New York City jet set, including fashion designer Calvin Klein, Andy Warhol, Halston, and Giorgio di Sant'Angelo.
Split into simpler sentences: She immediately invited them to one of her parties at her New York penthouse. The two guitarists performed at the party in private for the New York City jet set, including: fashion designer Calvin Klein, Andy Warhol, Halston, and Giorgio di Sant'Angelo.