(1) If the decision about the question whether evidence presented by a party is relevant depends on the court making another finding (including a finding that the evidence is what the party claims it to be), the court may find that the evidence is relevant—
(a) if it is reasonably open to make the finding; or
(b) subject to further evidence being admitted at a later stage of the proceeding that will make it reasonably open to make the finding.
(2) Without limiting subsection (1), if the relevance of evidence of an act done by a person depends on the court making a finding that the person and 1 or more other people had, or were acting in furtherance of, a common purpose (whether to effect an unlawful conspiracy or otherwise), the court may use the evidence itself in deciding whether the common purpose existed.