Is it possible to use application level middleware in express router?

Question

I've been playing around with setting up a basic atlassian-connect-express (ACE) application, and have modified the starter code provided by the ACE package to be suitable for serverless deployment. One of the problems I faced after doing this was that routing is now divided into stages, e.g. /dev, /prod. I did a bit of research and found that a way to deal with this would be to use an express Router and mount it to the appropriate endpoint for the stage being deployed to. The problem I then faced is that the authentication middleware provided by ACE seems to be application level and then can't be used by each router.

Typically the routes were added to the express app like this:

import ace from 'atlassian-connect-express';
import express from 'express';
import routes from './routes';
const app = express();
const addon = ace(app);

app.use(addon.middleware());
routes(app, addon);

and in ./routes/index.js

export default function routes(app, addon) {
    // Redirect root path to /atlassian-connect.json,
    // which will be served by atlassian-connect-express.
    app.get('/', (req, res) => {
        res.redirect('/atlassian-connect.json');
    });

    // This is an example route used by "generalPages" module (see atlassian-connect.json).
    // Verify that the incoming request is authenticated with Atlassian Connect.
    app.get('/hello-world', addon.authenticate(), (req, res) => {
        // Rendering a template is easy; the render method takes two params:
        // name of template and a json object to pass the context in.
        res.render('hello-world', {
            title: 'Atlassian Connect'
        });
    });

    // Add additional route handlers here...
}

I've changed ./routes/index.js to work as a router object and export that, however this leaves me unable to use the addon.authenticate() middleware

import ace from 'atlassian-connect-express';
import express from 'express';
import routes from './routes';
const app = express();
const addon = ace(app);

app.use('/dev', require('./routes'));

and in ./routes/index.js

const express = require('express');
const router = express.Router();

// Redirect root path to /atlassian-connect.json,
// which will be served by atlassian-connect-express.
router.get('/', (req, res) => {
    res.redirect('/atlassian-connect.json');
});

// This is an example route used by "generalPages" module (see atlassian-connect.json).
// Verify that the incoming request is authenticated with Atlassian Connect.
router.get('/hello-world', addon.authenticate(), (req, res) => {
    // Rendering a template is easy; the render method takes two params:
    // name of template and a json object to pass the context in.
    res.render('hello-world', {
        title: 'Atlassian Connect'
    });
});

module.exports = router;

Obviously having no knowledge of addon, the router cannot use that authentication middleware.

Is it possible to pass that middleware through to the router when attaching it to the application? If not, is there another way I can handle URL prefixes without using a router?