T1 is too small to handle International and transborder. T2 is too small to handle US + Rapidair + Domestic + GX.

Theoretically, T1 could take YQT, but probably couldn't take YOW Rapidair. T1 could take HKG, but since the first leg isn't sterile, that confuses YYZ-YVR...

So we get these weird anomolies:

T1: International--except HKG; Ontario--except YQT, YOW.

T2: Domestic, except Ontario; USA, except Hawaii...

But I don't think there's a simpler solution out there.