The SANParks employees, Tiyani Mabunda, 25, and former field guides Charles Mabunda, 29, and Duncan Mnisi, 34, appeared alongside provincial traffic officer Ellaraine Jennifer Brown, 28, and former traffic official Doctor Ngwenyama, 33, in the Nelspruit Regional Court.
Magistrate Andre Geldenhuys said defence lawyer Erwin Sithole was attending another matter in the High Court in Pretoria.
Ngwenyama, Mnisi, and the two Mabundas were arrested in February 2012 following the discovery of two white rhino carcasses in the Pretoriuskop section of the Kruger National Park.
Brown, who is married to Ngwenyama, was arrested in May 2012 after she was suspected of having transported a rhino horn out of the park.
The accused have not been asked to plead to charges of rhino poaching and are out on R20,000 bail each.
Geldenhuys postponed the trial to October 16 and 17.