SNAT NAT'ing to Both WAN Ports

Hi All, 

I have a internal interface and two outbound WAN ports. I have set up a VIP and assigned it to a rule going from WAN2 to the internal port, as that is the interface I want to snat on and this works fine. 

However, my WAN1 is my connection to the internet and the SNAT is being applied to this interface as well meaning the PC looses internet as WAN1 and WAN2 are different subnets. 

Is there any was to constrain the SNAT to just apply to traffic between internal and wan2? 

Thanks