We have a simple setup using 2 SIM cards in the RUTX12 with load balancing. We want to use load balancing for all traffic except for a group of a few internal IP address (5). These IP addresses must only go out via one of the WAN connection. In all of the similar examples, you have to specficy the gateway address for the traffic, but in this case, the gateway is unknown and can change (DHCP). It looks like this was possible on the older RUT routers using Load balancing configuration rules but this is no longer available.