Multi WAN Split

[haliparotin]

hi! i just want to ask how i can split the connection of my VPN because i have a 3 WAN and 3 Office using IPSEC

my actual setup today is like this

1st WAN - Main office (2nd Uplink) via Routing
2nd WAN - the 2 Branches (Main Uplink)
3rd WAN - Spare

Now i want this

1st WAN - Main office (2nd Uplink)
2nd WAN - 1st Branch (Main Uplink)
3rd WAN - 2nd Branch (3rd Uplink) i try this by routing, its not work

i Hope anyone can help me. Or give some idea.. Thank You