Using Dual-WAN failover but using the passive with a rule

[GShlomi]

As the subject says, is it possible to use Routing Rules to route a specific machine in the LAN to the internet via the Hot-Standby passive WAN connection?

Also - I'm trying to figure out all the "ip rule" "ip route" "iptables" stuff, can anyone point me to some guide?
Specifically, trying to understand the order things are getting processed...

Thanks in advance guys