The cheapest option is to transfer a call from one number to another by pressing when calling in the city network?

Question

Telephony

I thought about how best to do it ...
A phone call is answered and, if necessary, transferred to another handset or number.
I thought of one option, and even then it seems not reliable:
Use 2 dect phones and a base. There you can configure the reception of a call on one handset and then transfer to another. But since the line of sight is about 300m, I think that it may not finish.

Answer 1

Take a virtual PBX from a provider that provides landline numbers. For example, Beeline provides such a service.
Yes, and many others.

Answer 2

Is there a large distance between the subscribers who need to be forwarded? What equipment is used?