How to create it?

Question

Web traffic analysis

The essence of the problem is this. There is an Uzbek Internet zone called TAS-IX, and the external network is already the whole world. The problem is that providers in Uzbekistan charge the external communication channel at very expensive prices, and the channel for TAS-IX is free, or for mere pennies. How to arrange some kind of specific service that would help download files from an external channel by sending it to Uzbek servers.
The user sends a link from an external channel to the Uzbek server, the Uzbek server accesses the external server, the external server, having found the link, downloads the file and sends it to the Uzbek server, the Uzbek server creates a link in its space and transfers it to the user.
Thus, the economy of external traffic is obtained. Please help me how to write it all down technically?