[CH1MA3RA]

I would do something like this:

East
AL: NYY, BOS, TOR, BAL
NL: NYM, PHI, PIT, WSN

Midwest
AL: CWS, CLE, DET, MIN
NL: CHC, STL, MIL, CIN

Central
AL: KCR, COL, HOU, TEX
NL: ATL, TBR, MIA, NSH

West
AL: LAA, SEA, LVA, POR
NL: SDP, SFG, LAD, ARI