Order of the Court (Ninth Chamber) of 22 October 2021.#B v O and Others.#Request for a preliminary ruling from the Tribunal Judicial da Comarca do Porto Este - Penafiel – Juízo Trabalho.#Reference for a preliminary ruling – EU law – Principles – Article 18 TFEU – Equal treatment – Discrimination on grounds of nationality – Prohibition – Article 49 TFEU – Freedom of establishment – Joint and several liability of companies which form part of a group for debts resulting from an employment contract entered into by one of those companies – Exclusion by the legislation of the Member State concerned of companies that have their seat in another Member State.#Case C-691/20.