Texas Education Code - EDUC § 29.374. Right to Intervene in Civil Action

(a) A program participant, eligible child, education service provider, or vendor of educational products may intervene in any civil action challenging the constitutionality of the program.

(b) A court in which a civil action described by Subsection (a) is filed may require that all program participants, eligible children, education service providers, and vendors of educational products wishing to intervene in the action file a joint brief.  A program participant, eligible child, education service provider, or vendor of educational products may not be required to join a brief filed on behalf of the state or a state agency.