networks:
  net1:
  net2:
  net3a:
  net3b:

services:
  nginx-proxy:
    networks:
      - net1
      - net2
      - net3a
      - net3b

  web1:
    image: web
    expose:
      - "81"
    environment:
      WEB_PORTS: "81"
      VIRTUAL_HOST: web1.nginx-proxy.example
    networks:
      - net1

  web2:
    image: web
    expose:
      - "82"
    environment:
      WEB_PORTS: "82"
      VIRTUAL_HOST: web2.nginx-proxy.example
    networks:
      - net2

  web3:
    image: web
    expose:
      - "83"
    environment:
      WEB_PORTS: "83"
      VIRTUAL_HOST: web3.nginx-proxy.test
    networks:
      - net3a
      - net3b