A party making a peremptory challenge by motion or affidavit of prejudice regarding an assigned judge must submit it in writing to the assigned judge within 20 days after service of the order assigning the judge to the coordination proceeding. All plaintiff's or similar parties in the included or coordinated actions constitute a side and all defendants or similar parties in such actions constitute a side for purposes of applying Code of Civil Procedure section 170.6. Cal. R. Ct. 3.516 Rule 3.516