Gotta imagine the current conference leaders would make up 4 of the 5 you're asking about.
That list would include Wren, Chapman, Union, and Chapin in order of region.
From there, I really don't know. It could be skewed some in any direction. Last year 3 of the 4 district champs came from one region. Also, some regions have fewer teams than others, so it's always hard to tell until post season.