Complex sentence: Two auxiliary groups also support the organization, the Symphony Association of the Port Huron Area, and the International Symphony Association, and the group also receives support from the Port Huron Musicale and various sponsors and supporters, both private and commercial.
Split into simpler sentences: Two auxiliary groups also support the organization: the Symphony Association of the Port Huron Area, and the International Symphony Association. It also receives support from the Port Huron Musicale and various sponsors and supporters, both private and commercial.