config.json

server {
  listen 127.0.0.1:443 ssl;
  server_name site1.example.com;

  include common.conf;

  location / {
    proxy_pass http://127.0.0.2:8081;
  }
}

server {
  listen 127.0.0.1:443 ssl;
  server_name site2.example.com;

  include common.conf;

  location / {
    proxy_pass http://127.0.0.2:8082;
  }
}

server {
  listen 127.0.0.1:443 ssl;
  server_name site3.example.com;

  include common.conf;

  location / {
    proxy_pass http://127.0.0.3:8083;
  }
}