Brunch setup to output more than one CSS and JS file

brunch.js

exports.config = {
  files: {
    javascripts: {
      joinTo: {
        'js/app.js': [
          'web/static/js/vendor/**/*.js',
          'web/static/js/app/*.js'
        ],
        'js/dashboard.js': [
          'web/static/js/vendor/**/*.js',
          'web/static/js/dashboard/*.js'
        ]
      }
    },
    stylesheets: {
      joinTo: {
        'css/app.css': [
          'web/static/css/vendor/**/*.css',
          'web/static/css/shared/*.css',
          'web/static/css/app/*.css'
        ],
        'css/dashboard.css': [
          'web/static/css/vendor/**/*.css',
          'web/static/css/shared/*.css',
          'web/static/css/dashboard/*.css'
        ]
      }
    }
  }
  /* ... */
}