Chromecast and how to turn off AP Isolation

oriondon

I recently updated my modem to the Zyxel C3000Z which is really the VMG4825 I believe.  I have been having trouble chromecasting and read that I need to turn off AP (access point) isolation on my router however I do not see that option available.  I have also read that AP isolation can be called different things like, client isolation, guest mode and wlan isolation and even ssid isolation.  How do you turn that off on this router?

#CPE_Aug