The "29th brigade" sounds like a part of the Texas state troops/militia, not the Confederate army. As such, the "29th brigade" would not have beeen merged into anything--though individuals in that brigade would have enlisted in Confederate army units. Texas was divided into 33 militia brigade districts in 1861. A brief (very brief, due to space) discussion of the wartime TX state troops is in the book I recently coauthored, "Texas Burial Sites of Civil War Notables" (Hill College Press).