I have an Ash resource (say A) that has a relationship to B.

defmodule A do
    use Ash.Resource, data_layer: AshPostgres.DataLayer
    attributes do
        uuid_primary_key :id
        create_timestamp :inserted_at
        update_timestamp :updated_at
        attribute :x, :string, do: allow_nil?(false)
    end
    relationships do  
      belongs_to :b, B
    end
end

defmodule B do
    use Ash.Resource, data_layer: AshPostgres.DataLayer
    attributes do
        uuid_primary_key :id
        create_timestamp :inserted_at
        update_timestamp :updated_at
        attribute :x, :string, do: allow_nil?(false)
    end
end

How do I insert! multiple B and set the belongs_to relationship to an already inserted resource A?

Thanks.