Interacting with secondary images

I actually meant to add a snippet. Yes its super simple using the Docker executor, a primary image and a secondary dependency image:

    jobs:
      build:
        docker:
        - image: circleci/ruby:2.6.6-stretch-node-browsers
        - image: solr:8
          command: bin/solr -cloud -noprompt -f -p 8985

And so again the issue is that I need to get a file into my Solr server and run a command in there before invoking an API endpoint at port 8985. So the question is, is it possible to use docker commands to interact with the secondary container started via image: solr:8, or am I overlooking something simpler that gives my steps access to the contents of that container?