51. Defendant's additional claim
(1) A defendant may make an additional claim without the Court's permission if the additional claim is issued before or at the same time as he files his defence, or at any other time with the Court's permission.
(2) A person on whom an additional claim is served becomes a party to the proceedings if he is not a party already.
(3) When an additional claim is served on an existing party for the purpose of requiring the Court to decide a question against that party in a further capacity, that party also becomes a party in the further capacity specified in the additional claim.