Singleton for a factory inside another's factory traits = No ideas

gistfile1.rb

FactoryGirl.define do
  factory :user do
    first_name 'John Doe'
    last_name 'Doe'
    trait :yolo do
      first_name 'Spinder'
      last_name 'Man'
    end
    factory :spinder, traits: [:yolo]
  end

  factory :message do
    # Here I want :spinder and :user to be the same it the both traits
    # YOLO
    trait :from_spinder do
      association :from, factory: :spinder
      association :to, factory: :user
    end
    trait :from_john do
      association :from, factory: :user
      association :to, factory: :spinder
    end
    factory :message_from_spinder, traits: [:from_spinder]
    factory :message_from_john, traits: [:from_john]
  end
end