How to use another machine within Azure P2S VPN as a gateway?

Question

I have configured Azure P2S IKEv2 VPN and downloaded the VPN client (in machine it shows as PPP adapter) into 2 machines, one each in different countries. Say our IP addresses are 170.10.10.121 & 170.10.10.122 . From here on we'll call the site with .121 machine as site A.

My machine(.122) would like to use (.121) as a gateway, so that I could browse the internet in my computer using site A's public IP address. Is this possible or have I got this terribly wrong?

My end goal is that, we have multiple sites(B,C,D) that'd like to use the internal network as well as access public internet using site A. This site has dynamic IP address for public internet and port forwarding is not an option as ISP is non cooperative.

As shown in the below picture, machines PC-B-1,C-1,D-1 are trying to use the PC-A-1 as a gateway to access the internet through Site A. Thanks.

Answer 1

So this is the setup I am using as a work around. Since setting up a S2S is not an option for lack of infrastructure and lack of time, As given in the question, I installed P2S VPN agents in all the machines that is involved, from the machine whose internet we wanted (in site A) to be used by others, to all the other machines (in B,C,D). Now that all the machines are in Azure Vnet, I installed WinGate application at Site A machine and activated proxy.

Then I configured proxy on the rest of the machines in sites B,C and D to proxy through the machine in Site A using its Azure Vnet ip address.

Machines involved are all Windows 10.

This might not be the best solution, but given the extraordinary list of limitations definitely this was the quickest and easiest.

Let's see if we can get better and quicker solutions for the same :)

Meanwhile thanks for all the suggestions :)