Which Shall It Be?

Where I come from, God's Country, good manners are important.  It's another way to know if someone was "raised right."  Part of a proper upbringing is knowing the appropriate salutation in a given situation.

So let me give you a situation:  male/female marriage.

The appropriate greeting to the groom is "congratulations."

The appropriate greeting to the bridge is "best wishes."

So here's another situation:  same-gender marriage.

If it is two guys, do they both get the "congratulations" greeting?  If it is two girls, do they both get the "best wishes"?  If not, what metric should one employ to determine how the correct greetings are given to the betrothed?

This doesn't seem too serious a concern right now.  But through the diligent and unending work of so many, this will be a concern we must be ready to address at the drop of a hat, or at least before people start jumping brooms!  And this is one conundrum that gives me butterflies of excitement when I think about resolving it.  And being a part of that resolution.  Hooray for equality!  The train might be traveling slowly, but "I thought it could...I thought it could..."

(If for some reason I am never blessed with marriage to another human being, my second choice is to marry a metaphor.)