Return multiple DevSerices from BuildStep - Quarkus extensions

Question

I'm trying to create a client extension for an app I wrote, and the devservice for this will need both the app and mongo running (my app requires Mongo). Is there a graceful way to do this, and in a way that ensures Mongo is stood up first?

@BuildStep(onlyIfNot = IsNormal.class, onlyIf = GlobalDevServicesConfig.Enabled.class)
    public DevServicesResultBuildItem createContainer(LaunchModeBuildItem launchMode) {

        DockerImageName dockerImageName = DockerImageName.parse("my/app:1.0.0");

        // You might want to use Quarkus config here to customise the container
        OtherWebServiceContainer container = new OtherWebServiceContainer(dockerImageName)
                                                 .withEnv("whatever", "true")
                                                 .withEnv("otherenv", "something")
            ;

        container.start();

        Map<String, String> props = Map.of(
            "mynew.url",
            "https://" + container.getHost() + ":" + container.getPort()
        );
        return new DevServicesResultBuildItem.RunningDevService(
            FEATURE,
            container.getContainerId(),
            container::close,
            props
        )
                   .toBuildItem();
    }

Can I return a List from this method, where the first item would be for Mongo, and another for my app? Would I need a separate method to supply the other service (and if so, how to ensure Mongo starts first?)? Can I bring in the mongo extension for test only and just rely on that (while somehow requiring Mongo starts first?)?