I am currently ACTUALLY LOOKING at the actual cards.
Under the 1st account (SPG): 3 cards share the same, 2 cards share another, another 3 cards each have a different one.
Under the 2nd account (SPG): 4 cards share the same, another 3 cards each have their own
Surprisingly enough, and I just noticed this, some of the cards from the 1st account and some from the second share the same 4 digit code. The main account holder on the 1st account is myself, on the 2nd it's my wife. The cards that cross-share the same 4 digit code are not under the same AU.
Under the 3rd account (PRG) they all share the same.
Under the 4th account (Blue biz): 2 cards share, 2 cards have different.
Under the 5th account (Blue): All 3 cards different.
Under the 6th account (SPG) All cards the same except main account holder.
Under the 7th account (MB) 2 cards different.