Is there a way to sort by association property? something like /posts?$shallow=false&$sort[user.email]=1

Question

I have 2 models user and post with one-to-many relationship. I'm using feathers js and feathers-sequelize. The response I get when I query post is something like this:

[
  {
    "id": 1,
    "title": "Random title",
    "userId": 3,
    "user": {
          "id": 3,
          "email": "user@mail.com"
     },
   }
]

I want to sort posts by user.email , /posts?$shallow=false&$sort[user.email]=1 throws the following error.

How can I achieve this?