Dahua videointercom - VTO without VTH for 6 apartments (each aprtmnt with smartphone DMSS)

[DiliMe]

Hi guys,
Quick question here. I know this is not an IP cam question, but hopefully you can help.

We're 6 apartments in an old building, looking to install on the fence 1 x Dahua VTO6221E-P, but we do NOT want any wires inside the building for internal intercoms (so not VTHs).
Is it possible to program the VTO with 6 x individual apartments, while for each of the 6 apartments to have multiple smartphone iDMSS or gDMSS apps installed?
The idea is from the fence VTO to call an apartment # and only the smartphones associated with the apartment # to be ringing.
Any extra license needed if we will not have VTHs?

Thank you!

 

[Albi]

Apartment Systems from DAHUA can't work without VTH.

 

[DiliMe]

Apartment Systems from DAHUA can't work without VTH.

OK, thank you for the clarification!
Probably the only option from Dahua to NOT wire inside the building would be to use WiFi VTH indoor panels?
Now comes the next question: The WiFi indoor panels would have to in the same WiFi SSID subnet with the VTO (external unit)?