I dunno how these work but maybe you could make one primary with sim in, then daisy chain the others to it with network cable.
If it has DHCP capability which it should you only enable that service on the primary router and disable it on the rest.
Give the rest of the devices a static IP eg: Primary: 192.168.0.1, Secondary 192.168.0.2 and so on.
In your DHCP range you just start the range at 192.168.0.4 - 192.168.0.10 depending on the amount of devices you want to connect.
I connect my B683 to a Mikrotik router, and then via that to a netgear switch, and the rest of the house with cable ... , if I did not need DDNS, I could do away with the Mikrotik if need be, but it allows a lot of other functionality as well ...