Article 21 of the Convention of 27 September 1968 on Jurisdiction and the Enforcement of Judgments in Civil and Commercial Matters, as amended by the Convention of 9 October 1978 on the Accession of the Kingdom of Denmark, Ireland and the United Kingdom of Great Britain and Northern Ireland and by the Convention of 25 October 1982 on the Accession of the Hellenic Republic, is not applicable in the case of two actions for contribution to general average, one brought by the of the hull of a vessel which has foundered against the owner and the of the cargo which the vessel was carrying when it sank, the other brought by the latter two parties against the owner and the charterer of the vessel, unless it is established that, with regard to the subject-matter of the two disputes, the interests of the insurer of the hull of the vessel are identical to and indissociable from those of its insured, the owner and the charterer of that vessel.