Select a single child from list

Hello!
I have a collection (‘locales’) with a field of countries which contain a list of provinces/states.
I wonder if it is possible to select a country and based on that get a list of its states and be able so select one.

This is how looks my config so far, but i haven’t been able to do such a thing

collections:
  - label: "Locales"
    name: "locales"
    folder: "public/data/locales/"
    create: true
    identifier_field: "country"
    format: "json"
    fields:
      - { label: "Country", name: "country", widget: "string" }
      - label: "Provinces/States"
        name: "provinces"
        widget: "list"
        required: false
        fields:
          - { label: "Province/State", name: "province", widget: "string" }
  - label: "Platform"
    name: "platform"
    folder: "public/data/platforms"
    create: true
    identifier_field: "name" 
    format: "json"
    fields:
      - { label: "Name", name: "name", widget: "string" }
      - label: "Country"
        name: "country"
        widget: "relation"
        collection: "locales"
        search_fields: ["country"]
        display_fields: ["country"]
        value_field: "country"

Hey there, @astrank :wave:

I am not seeing any sites associated with the email account you used to register for the forums. Can you please share a link to the site you are hosting?

Thanks,
Hillary