business letters

[Unregistered]

When I am addressing a married couple with different last names I am not sure how to list. Here is how I do it for married people with the same last name:
Mr. and Mrs. John Smith
123 Main Street
Your Town, USA 12345

Dear John and Mary,

But when I have a married couple with different last names I am not sure how to address them in the top line of the above example.

Thanks,
Jeff Dickison

[Anglika]

Mr Smith and Ms Jones