"The second principal objection to Order 18A was that it purports to extend the jurisdiction of the Court in a manner not authorised by s.25. In essence the complaint rested on two elements, first, that persons could be joined effectively as plaintiffs without their consent, and, second, that the result of a group proceeding is intended to bind conclusively all members (except those who are able to and choose to opt out), so as to create res judicata between them and the defendant. Indeed, r.18A.27 requires the Court at the time of judgment to 'describe or otherwise identify' all such group members who by para (b) are explicitly stated to be bound. The defendant asserts that under O.18A parties may be so affected who have no knowledge whatever of the proceedings and who will not have been served under the conventional rules as to service, including those permitting substituted service. In my opinion there is no reason why the Court should not effectuate by rule of court these consequences of group proceedings. Unless it be asserting jurisdiction over persons outside the jurisdiction..., this Court may make rules as to how parties are joined and are represented in proceedings in the Court. Substituted service not infrequently is ineffective to bring proceedings to a party's notice..., but the Court recognises that that may be a necessary consequence of enabling certain plaintiffs to obtain relief to which they are entitled. There is no direct equivalent for plaintiffs, but the practice has existed for many years of binding unwilling plaintiffs by joining them as defendants to whom substituted service may be directed. More importantly, in the present context, for many centuries... the courts have permitted, in one way or another, parties to sue (and be sued) by representatives who have either claimed the right to sue on behalf of others or, more frequently (but not invariably) and in recognition of such claims, have been authorised or permitted by the courts in more recent centuries to sue or be sued on their behalf.... The Chancery practice, later adopted in Judicature Act rules, has been authoritatively expounded in relation to both the 'traditional' representative suit... and Part IVA of the Federal Court Act in, respectively, Carnie v. Esanda Finance Corp Ltd.... and Wong v. Silkfield...." Joinder is clearly a matter for courts to prescribe as a matter of practice and procedure, but one may concede that the binding effect of judgments and the principles of merger of judgments, res judicata and issue estoppel are substantive. Insofar as O. 18A purports to change or expand those rules then one could only justify r.27 if it were possible to treat this attempt to bind absent parties as no different in substance from that recognised as flowing from the effect given to orders under O.18 and the like. Doubtless the classes represented by 'group members' as defined by the new Order... are wider than even the High Court... was prepared to encompass under the existing procedures, but the means of communicating with them and their rights to opt out are more extensive. ... More importantly Rule 18.04, unlike the former O.XVI r.9, specifically provides in para (1) that judgments and orders under that rule "shall bind the parties and all persons as representing whom the parties sue or are sued", though leave is required before the judgment or order is enforced. The binding force of such orders is thus dealt with explicitly and the rule-making power ought to taken as extending to justify r.18A.27, unless the subject-matter of the new Order is to be seen as something quite different in character. No doubt the procedure is more elaborate and its scope is significantly wider, but in my opinion it is essentially an order permitting representation of absent parties, as are Orders 18 and 16. Whatever be its practical effect, Order 18A merely creates a "new form of representative proceedings", as their history demonstrates and as the High Court described the almost identical provisions of the Federal Court Act Part IVA in Wong.... I do not accept the defendant's analysis of the new procedure embodied in Order 18A. Consequently in these respects it did not go beyond the Court's rule-making power."