[Evidlo]

You might be able to host an instance of Asterisk [0] and set up call forwarding based on the extension [1].

I haven't played with Asterisk before, so I'm not 100% certain.

[0] https://en.wikipedia.org/wiki/Asterisk_(PBX)

[1] https://www.voip-info.org/asterisk-call-forwarding/