Random except for the two Open Finalists from last year.
They are separated first I'm quite sure.
That said, again, this is another consideration that's been addressed.
Personally I'd prefer no seeding as once you seed teams there's a risk you might start seeing the same faces in the semis.
Just my opinion to make sure its always a mix and if you draw a group of death - Too bad.
(Yes, that was meant for you CIC)