Details ... :- 
4 NEW clubs in 2012.
2 NEW in North Zone = 10.
2 NEW in South Zone = 12.
FIXTURING: 12 teams means 11 rounds if everyone is to play everyone else once - there simply aren't enough weeks to be fortnightly.
Two solutions come to mind:
A: play back-to-back Rnds1&2, Rnds4&5&6, Rnds8&9&10
B: play 9 rounds with teams seeded from last year so each team misses both a top and a low club, or 2 middle order.