Front Gate Nice It4Wifi guests having remote access

Hello,

I am trying to set up access Nice IT4WiFi for our front gate.

I installed it in my home where I have a home hub as HomePod mini.

For me it works fine but I am trying to give access to my neighbours who should be able to control it remotely as well.

They can only control it if they are connected to my Wi-Fi

Is there a way to set it up so they can only see the front gate accessory and not my other home accessories?

Of course it would be much easier if I could set up the Nice unit so it works over their native app and HomeKit, but that is not a possibility. I can only choose one.

Thanks