Using dataproxy for access to datasource

How can I configure grafana to access the datasource via another grafana server using dataproxy? For example:

One way to do it would be to have a proxy (like nginx) on the server where Grafana 2 is that proxies the datasource.

Another way is to go through the Grafana API (have never tried this though) and call the datasource that way:

I am very new to Grafana.

Can you explain the Grafana 1 to Grafana 2 TCP 3000 connection and what that is doing?