How to delete reference documents of a sub document in mongoose?

Question

I have a parent document, ParentDoc, with an embedded sub document in mongoose.

If I delete an embedded sub document, how do I ensure all of its reference documents, RefObject, get deleted?

With embedded documents, .remove() middleware will only run when you call .remove() on the parent document. So I can't trigger a pre remove hook on the subDocSchema and delete the referenced object in there.

Is there anyway to delete a subdocument's reference objects when the subdocument is deleted? If not, is this a case where I should have instead made the sub document a referenced document?

const parentDocSchema = new mongoose.Schema({
  name: String,
  subDocuments: [subDocSchema],
});

const ParentDoc = mongoose.model("ParentDoc", parentDocSchema);

const subDocSchema = new mongoose.Schema({
  name: String,
  refObjects: [
    {
      type: mongoose.Schema.Types.ObjectId,
      ref: "refObject",
    },
  ],
});

const RefObject = mongoose.model(
  "RefObject",
  new mongoose.Schema({
    name: String,
  })
);