4. The group-level resolution authority shall communicate any measure proposed by the ultimate parent undertaking to the authorities that are members of or participate in the resolution college. The group-level resolution authority and the resolution authorities of the subsidiary undertakings, after having consulted the supervisory authorities, shall do everything within their power to reach a joint decision, as referred to in Article 17, within the resolution college regarding the identification of substantive impediments, and, where necessary, regarding the assessment of the measures proposed by the ultimate parent undertaking and the measures required by the authorities in order to address or remove the impediments. When doing so, they shall take into account the potential impact of the measures in all Member States where the group operates.