Tex. 1st. Ct. App. L. R. 1.3

As amended through August 27, 2024
Rule 1.3 - Notice of and Assignment of Related Cases in Original Proceedings
(a) At the time an original proceeding is filed in either the First or Fourteenth Court of Appeals, the relator must file a notice indicating whether any related appeal or original proceeding has been previously filed in either the First or Fourteenth Court of Appeals. The notice must include the caption, trial court case number, and appellate court case number of the related appeal or original proceeding.
(b) If any related appeal or original proceeding has been previously filed in or assigned to either the First or Fourteenth Court of Appeals, the clerk of the appellate court receiving the original proceeding must assign it to the court of appeals in which the related appeal or original proceeding was previously filed.
(c) If related appeals or original proceedings have been filed in both the First and Fourteenth Courts of Appeals, the clerk of the appellate court receiving the original proceeding must assign it to the court of appeals in which the most recent related appeal or original proceeding was previously filed or assigned.

Tex. 1st. Ct. App. L. R. 1.3