GL'750S More than one ip class on lan side


for some reason I need to setup more ip class on lan side (and wifi too) maybe with own dhcp server (but this couldn’t be a problem).
I don’t need to talk to these VLAN (I could label the ip class in this way?) but I need that all classes can access internet (in every way is up, such as the main lan ip class).

I’ve basically tried to add a 2nd ip address but the router has crashed, than I have to reset and reinstall the config)

Thanks to everyone that could help

Can you post what did you set exactly?