(a) "Underlying case" means a trial court case number that is filed in one of the counties that comprise the jurisdiction of the First and Fourteenth Courts of Appeals and is subsequently the subject of either an appeal or original proceeding in the First or Fourteenth Court of Appeals.(b) "Related" means arising from the same underlying case or a case that has been remanded by either the First or Fourteenth Court of Appeals and includes cases severed from the main case.(c) "Previously filed" means that a case has been opened at either the First or Fourteenth Court of Appeals and that an appellate case number has been assigned to the underlying case.Tex. 1st. Ct. App. L. R. 1.1