(a) a proceeding (in this sub-section referred to as the 'relevant proceeding') is pending in the Supreme Court (in this sub-section referred to as the 'first court'); and
(b) it appears to the first court that -
(i) the relevant proceeding arises out of, or is related to, another proceeding pending in the Supreme Court of another State or of a territory and it is more appropriate that the relevant proceeding be determined by that other Supreme Court;
(ii) having regard to
(A) whether, in the opinion of the first court, apart from this Act and any law of the Commonwealth or another State relating to cross-vesting of jurisdiction, the relevant proceeding or a substantial part of the relevant proceeding would have been incapable of being instituted in the first court and capable of being instituted in the Supreme Court of another State or Territory;
(B) the extent to which, in the opinion of the first court, the matters for determination in the relevant proceeding are matters arising under or involving questions as to the application, interpretation or validity of the law of the State or Territory referred to in sub-sub-paragraph (A) and not within the jurisdiction of the first court apart from this Act and any law of the Commonwealth or another State relating to cross-vesting of jurisdiction; and
(C) in the interests of justice -
it is more convenient that the relevant proceeding be determined by that other Supreme Court; or
(iii) it is otherwise in the interests of justice that the relevant proceeding be determined by the Supreme Court of another State or of a Territory -
the first court shall transfer the relevant proceeding to that other Supreme Court."
(Emphases added).