Yeah!
Congratulations!
Must have been the cheesecake..........
Well it's not a two letter group but that still leaves a LOT of groups.
I'm lazy so I'm not spelling them out (and you'll just have to forgive me if I abbreviate wrong)..........
AXO
ADPi
AEPhi
AGD
AOPi
ASA
AST
AXiD
DDD
DPhiE
GPhiB
KAT
KKG
PhiSS
PiBPhi
SDT
SSS
TPhiA
ZTA
I'm going to guess AOPi. Don't know why, but that sounds about right.
Now I know that some of these rarely do AI but I'll let someone else narrow those ones down.
Edited: because I skipped right over a couple.