So we have three households that have multiple people to invite. For example, FH sister and her fiancé have an invite, but her daughter who is 21 lives at home and we want to invite her too. So would I address to ms FH sister & Mrs Fh sisters fiancé & Miss FH niece?
Or the other two are friends who one is a married couple and their cousin lives with them, and the others are my friends that are mother and daughter, but they can bring a guests if they want.
I just think it is silly to send two invitations to the same house.