Dual WAN setup LB2120?

Hi all,

Hope someone can help please.

I have two LB2120 4G modems. They run together feeding into a dual WAN setup on my ASUS router.

Now both connect to the router fine, however I am unsure on the IP settings. I basically want to be able to view both LB2120 modem interface pages right from the ASUS router. However, I can only ever access one of the modems at a time.

LB2120 One = IP: 192.168.5.1. Subnet: 255.255.255.0

LB2120 Two = IP: 192.168.4.1 Subnet: 255.255.255.0

ASUS Router: IP: 192.168.1.1 Subnet: 255.255.255.0 Gateway: 192.168.1.1

If I turn off one of the LB2120, I can always access the other by typing in the modem IP. If both are on at the same time, only one is ever accessable, not both. I thought having changed the IP's so they dont conflict, this would work.

Any ideas or advice please?

Matt