Prevent IP Scanning on guest network

[Sunny-E]

I bought a AC3000 RBR 50 router with satellites. Its good that Guest network doesn't allow devices to connect to each other. However, they are still "visible". If I run an IP scanner from a guest network devices, it can see IP address of every device that is on the LAN, though can't connect to it. I am guessing, behind the scenes its an issue with how IPTables are configured. Maybe its Rejecting packets vs. Denying. As a result, the guest devices knows that there are other devices out there and their IP addresses. 

Is there a way to prevent a guest device to scan IPs on the LAN network? 

Is this a bug in Orbi's guest network implementation? Should it not make other devices completely invisible to guests. 

[CrimpOn]

I believe you are correct. When the setting is "not allow" connection to other devices, Orbi appears to block TCP and UDP connections, but not ICMP packets.  On other Netgear products, Guest devices are placed into a different IP subnet, so they can be totally isolated.  I have so little experience across brands of routers that I lack perspective as to whether what Netgear did with the OrbGuest network is "common practice" or "uncommon".