Rails Admin Polymorphic association model in one field

Question

I have these four classes which are combined with polymorphic association. Podcast and Article use adapter_inhouse_banner for the inhouse_id and inhouse_type.

adapter_inhouse_banner also keeps an inhouse_banner_id column which has a foreign key connection with the id on inhouse_banner

For context: The idea behind inhouse banners is to choose articles and podcasts to be displayed in a seperate pages with ids called inhouse banners

class Podcast < ApplicationRecord
  has_many :adapter_inhouse_banners, as: :inhouse
end

class Article < ApplicationRecord
  has_many :adapter_inhouse_banners, as: :inhouse
end

class AdapterInhouseBanner < ApplicationRecord
  belongs_to :inhouse_banner
  belongs_to :inhouse, polymorphic: true
end

class InhouseBanner < ApplicationRecord
  has_many :adapter_inhouse_banner
  has_many :articles, through: :adapter_inhouse_banner, source: :inhouse, source_type: 'Article'
  has_many :podcasts, through: :adapter_inhouse_banner, source: :inhouse, source_type: 'Podcast'
end

I currently have my rails configuration setup as such:

config.model InhouseBanner do
  edit do
    field :title
    field :articles
    field :podcasts
  end
end

It looks like this

I want to combine the articles and podcasts in one field make it look like this