WAN port work together with wifi extender (relayd)

I have got my second router B connected to the access point of the main router A. B is configured as a wifi extender described in this document: https://openwrt.org/docs/guide-user/network/wifi/relay_configuration The LAN interface ip is: The ip got by the lan ports are: 192.168.1.*

I have another broadband line which I wish to utilize as well. When I plunged it in the wan port of router B. The router seems automatically configured to use WAN as gateway, which can be confirmed with “ip route” and “traceroute” in the console.

However, if I configure the lan ports as static ip: 192.168.2.* and gateway: They failed to connect to WAN

You'll have to connect the second broadband line to RouterA and use mwan3 or some other way to load balance or failover between the two connections.

Thanks for the quick response. However, due to the far distance between the other broadband line and router A I still wonder if it's possible to just route some/all of the ports in router B to it's own wan port while keep the connection between both of the routers.

I don't think it's possible with this weird relayd mode, but maybe someone else has a better idea.