Bastion host docker

[tomikonio]

Hi,
How can I configure molecule to use one of the docker hosts as a bastion host ?
I have put the following argument in molecule.yml:

provisioner:
  name: ansible
  connection_options:
    ansible_ssh_user: root
    ansible_ssh_common_args: '-o ProxyCommand="ssh -W %h:%p -q instance"'

But this command does not do anything and the playbook still runs from my machine instead of running from instance.
Am I missing here something ?
Maybe the docker containers are not accessed via ssh at all ? (makes sense)
If so how can this be configured properly ?