How to group mixins?

Need Help
#1

How to group mixin? Now on the page I turn to the title and I need hero_1.title

    partners:
        name: Категория Партнеров
        fields:
            hero_group:
                tab: Edit
                name: Первый экран 1
                type: section
                fields:
                    hero_1:
                        name: Первый экран 1
                        type: mixin
                        source: builder_hero_1
#2

hero_1 is the name of the mixin and it won’t create a field, so if it contains another field named title, this is accessed via .title