title: docker-compose build --parallel - run command before build specific image
body: <p>my <code>docker-compose.yml</code> file is below.</p>
  <p>I want to build parallel those images - I am running the a command <code>docker-compose build --parallel</code></p>
  <p>BUT I want to run a command before it builds the images of <code>service2</code> &amp; <code>service3</code> while building <code>service1</code> - parallel.</p>
  <p>When the command will be finished it will join to the building-parallel-process.</p>
  <pre><code>version: '3.4'
    services:
      service1:
        image: &quot;company/service1:${TAG}&quot;
        build:
          context: ./folder/service1/
          dockerfile: Dockerfile
      service2:
        image: &quot;company/service2:${TAG}&quot;
        build:
          context: ./folder/service2/
          dockerfile: Dockerfile
      service3:
        image: &quot;company/service3:${TAG}&quot;
        build:
          context: ./folder/service3
          dockerfile: Dockerfile
  </code></pre>