Tex. Gov't Code § 843.201

In accordance with rules adopted by the board of trustees, the governing body of a participating subdivision by order may authorize the establishment of credited service and prior service credit in the retirement system for service performed in a public hospital, utility, or other public facility or governmental function during a time the facility was operated or function was performed by a unit of government other than the subdivision and before the date that the public hospital, utility, or other public facility or governmental function was taken over by the subdivision.