Queries regarding Field Level permissions?

I have a Realm Object , named Source .

class Source {
  ObjectId _id,
  String content,
  Bool published,
  String title,
  String created_by,
  List<String> subNotes,
  List<String> access_list,

I want the content field to available to owner ( is determined by created_by) at all time, and for rest of the user’s only if the published field is ‘true’. I was trying to implement this by using the field level permission on ‘rules’ section on Atlas App Services ?

I am unable to achieve this with something like below;

  "fields": {
        "content" : {
            "read" : {
                "published"  : true
            "write" : {
                "published"  : true

Is is possible to achieve this using field level permission ?