City of Irving v. Pak
In City of Irving v. Pak, 885 S.W.2d 189 (Tex. App.--Dallas 1994, writ dism'd w.o.j.), the Dallas Court of Appeals held the employees of the City of Irving could appeal the denial of their summary judgment motions, but the City of Irving could not appeal because the City's motion for summary judgment was not based on official immunity due to the acts of its employees. Id. at 193.
Instead, the City of Irving asserted a separate claim of immunity that the plaintiffs did not meet the statutory requirements to sue the City. Id. (The incident was not based on the operation of a motor-driven vehicle or a condition or use of tangible or real property.)