I have a web server(A) running on private network and I have another host machine(B) within same private network.
example: Web Server A: private ip: 10.128.0.2 Application running on port: 8088 Host machine B: Private ip: 10.128.0.5 public ip: 54.34.23.56
The client send the request the host machine B https://54.34.23.56:8088. The host machine B transfer the request to Web Server 10.128.0.2:8088. And the client get back the response from application running on web server.
You can use nginx proxy_pass to solve your problem.