In searching the forums for this particular issue I found many posts but the only one that seemed to describe my problem was this one.
So I faithfully followed the steps suggested by Jo Vens, but other devices on the network are still visible, even if they are unreachable when pinged.
Specifically the steps followed were: 1. Created whitelist - added router LAN port mac address and LAN gateway IP 2. Created L3 ACL list - allow DNS, DHCP, HTTP & HTTPS 3. In WLAN Advanced options: - on the Access Control tab select L3 ACL list previously created - on the Others tab, select both Isolation check boxes and select the whitelist previously created
Saved and re-started the access points.
As stated, I am able to get to the internet, and all but, other devices are still visible to applications like Fing on iOS.
I would've thought that the steps above would essentially give each device a pipe only to the internet, with nothing else on the network visible.