I have Contact cards for my father- and brother-in-law, let's call them John Smith and Johnny Smith (he's a Junior). My father-in-law doesn't use Facebook, but my brother-in-law does, and since he goes by John Smith on Facebook, Mountain Lion associated my father-in-law's card with his account (even though I had birthdays for each card - now my father-in-law has two birthdays...).
Is there any way I can correct it to choose by brother-in-law instead? I tried disabling Contacts integration from System Preferences, then renaming them to be John Smith, Sr. and John Smith and turning it back on. It remained connected to my father-in-law.