The examples and sample code show that 2 way communication with avatars and voip can be done; but can you have a group session like in the vTalk app? where 2 or more people come together and talk?
If so, how is it done? The VOIP Manager sample seems to be made for 2 people only
Also - worth checking out https://developer3.oculus.com/documentation/platform/latest/concepts/dg-cc-parties/ to make sure that you have built support for handling Parties into your app, such that the Voip doesn't break if a party launches into the app together.