BLE Mesh - Multi Device connect to mesh network

[mm_1993]

Hello All
I'm using ble mesh fast prov example IDF

I wanna know what should I do if I want to connect to the mesh network with at least two mobile phone?
All of nodes is in Proxy and Relay mode config and thats mean each nodes can connect to the a client(phone) Separately ..

so I dont know that when a phone disconnected from mesh network is receive any callback ?
after that when a new mobile phone that wanna connect to the mesh network how can see the node? in esp example after provision complete you can NOT see the node with new devices.
and which parameter should I save for a device in my nodes that after reset mcu didnt need to provision again ?

thank you so much
best regards