A modified low-pressure vapor-phase selenization process that enables controlled incorporation of multiple chalcogens in ZnSe semiconductor thin films has been demonstrated. Growth of polycrystalline ZnTexSe1-x films and modification of the Te/Se ratio by varying the reactor pressure have been observed. Te incorporation results in the lowering of the band gap to 2.45 eV from 2.65 eV for pure ZnSe and reduction in resistivity by a factor of 3. The increased Te incorporation in the film correlates with the value estimated from modeling of the gas dynamics of the system and is independently confirmed by XRD. These results indicate that the Te-2-Zn reaction is competitive with the Se5-7-Zn reaction under the experimental conditions investigated.