Texas Code of Criminal Procedure - CRIM P Art. 36.03. Invocation of Rule

(a) Notwithstanding Rule 614, Texas Rules of Evidence, a court at the request of a party may order the exclusion of a witness who for the purposes of the prosecution is a victim, close relative of a deceased victim, or guardian of a victim only if the witness is to testify and the court determines that the testimony of the witness would be materially affected if the witness hears other testimony at the trial.

(b) On the objection of the opposing party, the court may require the party requesting exclusion of a witness under Subsection (a) to make an offer of proof to justify the exclusion.

(c) Subsection (a) does not limit the authority of the court on its own motion to exclude a witness or other person to maintain decorum in the courtroom.

(d) In this article:

(e) At the commencement of a trial, the court shall admonish each witness who is to testify as to those persons whom the court determines the witness may talk to about the case before the trial ends and those persons whom the witness may not talk to about the case.  The court may punish as contempt a witness who violates the admonishment provided by the court.