How to enable "Allow guests to see each other"

Running Fing (free edition) with both my iPad & iPhone on the guest network, each of those can see all the devices on the main network, but cannot communicate with any of them. They can't access their web servers or telnet to them or even ping them. And the 2 iDevices can't see each other at all.

So the label of the GUI setting to "allow guests to see each other and access my local network" is pedantically correct. It doesn't say anything about allowing or not allowing guest devices to see the existence of the non-guest devices.

With your devices on the guest network, can they do anything more than "see" devices on the main LAN?

Unfortunately, setting those 2 variables I mentioned earlier seems to only affect the GUI. "Allow guests to see each other and access my local network" is checked but the guest devices still cannot access the main LAN devices.

Now I'm trying to understand endis_wlg_guest_wireless_isolation and endis_wla_guest_wireless_isolation. Those are both 0 which would seem to indicate isolation is off, but maybe they're backwards. (What is "endis" anyway?)  Grumble. I wish the GUI checkbox was simply enabled and worked.