Cal. Const. art. I, § 30

(a) This Constitution shall not be construed by the courts to prohibit the joining of criminal cases as prescribed by the Legislature or by the people through the initiative process.
(b) In order to protect victims and witnesses in criminal cases, hearsay evidence shall be admissible at preliminary hearings, as prescribed by the Legislature or by the people through the initiative process.
(c) In order to provide for fair and speedy trials, discovery in criminal cases shall be reciprocal in nature, as prescribed by the Legislature or by the people through the initiative process.