Wifi SSID with routed interface for IoT devices

[mad_ady]

I plan on adding a few wifi IoT devices in my house (Sonoff switches) that I'd like to separate from my main LAN and have a different address space and firewall rules for devices in that LAN. I still want DHCP in the LAN (though I can live without it). I'm using RMerlin's build on a RT56U.

I was thinking of setting up a guest SSID, but I'm not sure how to assign it to a different IP class and unbridge it from br0. I'm confortable to do this via shell and startup scripts, but if somebody's already done it, I'd like to read a bit on it first.

Thanks