How to specify directories in sbt-uglify options

Question

I have a project based on play framework. I'm using sbt-uglify plugin to minify & concatenate the js files

In my build.sbt I have defined

UglifyKeys.uglifyOps := { js =>
  Seq((js.sortBy(_._2), "javascripts/all.min.js"))
}

The above code includes all the js files. However I want to do something like

UglifyKeys.uglifyOps := { js =>
  Seq(include all js only from controllers folder, "javascripts/controllers.min.js"))
  Seq(include all js only from services folder, "javascripts/services.min.js"))
}

How can I do this without using sbt-concat?