You would accomplish this with two easy rules, one for each interface.
Simply create a rule something like this:
Proto Source Port Destination Port Gateway
* 10.10.10.0/24 * any * Default/wan2/wan3, etc.
(or just choose lan
subnet, dmz subnet, etc.)
Proto Source Port Destination Port Gateway
* 192.168.0.0/24 * any * Default/wan2/wan3, etc.
(or just choose lan
subnet, dmz subnet, etc.)
Just select which gateway you want the traffic routed through.