Madame to Madam to Ma'am (Unfunny Response to Request for Advice)
Madame is the French and equivalent of Madam, with the stress on the other syllable.
Over beer, wine and/or whiskey, just tell them the ladies would be flattered to be called "Madame".
Once you've jumpstarted the process, the stress will shift to the right syllable and then you could nudge it along later on in the camaraderie by using Ma'am in their presence. Then all you have to do is wait until their look of confusion transmutes into a question.
You can then impress them with the word "elision" which is the techie term for skipping the "d" (or other bits and pieces of words and phrases).
Enjoy!