How to address two Doctors with different last names

I have read the answers to other posts, however we might be in a unique situation. Many of our guests are medical doctors married to medical doctors and in some cases the ladies have keep their maiden names. We are friends with the ladies and acquaintances with the gentlemen.
Who should be listed first the lady or the gentleman? How do we address the inner and outer envelopes? How do we address the envelopes for the Doctors and their wives who are not medical doctors? Should it be Dr. Gary Smith and Mrs. Gary Smith or Dr. Gary Smith and Mrs. Smith?
Appreciate your help.

Rebecca Black, Etiquette By Rebecca

Dear Andrea,

Actually, this is a common question. Married doctors would be addressed as The Doctors Smith on both the outer and inner envelopes. If both are doctors and have different last names, the names would be listed in alphabetical order (on separate lines) with “and” in between the names. The inner envelope would read: Dr. Doe and Dr. Jones (alphabetical). A doctor and wife, who is not a doctor, would be addressed as: Dr. John Smith on the first line and Mrs. John Smith on the second line.


Thank you so much! You are just fabulous!