In Bleeker v. Villarreal, 941 S.W.2d 163, 169 (Tex. App.--Corpus Christi 1996, writ denied), the court held that under Chapter 15 of the Civil Practice and Remedies Code, in a case involving several defendants, to successfully challenge venue, the challenging defendant must: (1) show that venue was not permissible in the county of suit for any defendant; (2) show a mandatory venue provision required transfer to another county; (3) establish that the co-defendant whose presence made venue proper was improperly joined, or; (4) obtain a severance. Id. at 169.