Tom., if you hold a HMS permit, that is good for the person who holds the permit only.
If a charter boat has a federal multi species permit everyone on the boat is covered. As I understand it, a charter/party boat must have this federal multi species permit to fish in federal waters (3 miles out, EEZ zone).
Not every charter boat will have a multi species permit as some do not fish federal waters.
That is how I interpret this regulation from all that I have read on it.