Hello,
My name is Magdiel
Systems and computer engineer, with 5 years of experience in voice and data.
The solution you propose is not managed, I think it is even illegal.
The alternative that I have implemented for companies that have branches in several countries is to implement an IP PBX.
That allows to perform:
-called local SIP Trunk / FXO etc, according to plan contracted with VoiP provider
-international call making from extension to extension, without using VoiP provider services.
Example.
User1-- Extension 500 -Local
User2 - Extension 600 - Remote (US)
Both users communicate over the Internet (SIP).
Both users can have their extension configured on their laptop / mobile phone / desktop (for this last will require more adjustments).
also conduct conferences using the license acquired from IP PBX
I would be interested to know more about the project and provide you with the solution.
Pending your comments.
Regards..