I wonder if I didn't get your question for my English. Do you know "how you can call the family members of your host family"? If so, I would say: (for all of them) みなさんのことを なんて よんだら いいですか。(for one of them whom you talk to) (あなたのことを) なんて よんだら いいですか。If I understood wrong, please let me know.