An official of the European Union Delegation in a third country must organize an emergency meeting with colleagues from the European Commission and the Defense Ministries of the Member States to discuss an imminent geopolitical crisis. The objective is to share sensitive documents containing classified (non-public) information and maintain a secure command chain. According to the functions and operational framework of the European External Action Service (EEAS) and the EU's security policies, what is the most appropriate approach to ensure the security of the data and effective collaboration in this specific scenario?