Theo's pointed out a glaring problem with the system previously posted.

The following replaces it:

Round One
A- 4 PS vs. 5 WL *
B- 4 WL vs. 5 PS *
C- 2 PS vs. 3 WL
D- 2 WL vs. 3 PS
Top ranked sides receive a bye

Round Two
1- WL 1 vs. PS 1
2- Winner A vs. Winner B *
3- Loser C vs. Loser D *
4- Winner D vs. Winner C

Round Three
A- Winner 1 vs. Winner 4
B- Loser 1 vs. Loser 4 *
C- Winner 2 vs. Winner 3 *

Round Four
1- Loser A vs. Winner B *
2- Winner A vs. Winner C *

Grand Final
Winner 1 vs. Winner 2