Three members of the Whanganui Boxon side were in the Manawatu Mustangs team who tumbled to a 30-20 defeat against the Taranaki Sharks in the deciding match of their series on Sunday.
Taranaki won the first game in Hawera in May before Manawatu took out the second in June.
At Fitzherbert Park in Palmerston North, Manawatu led 10-6 at the break but Taranaki had a big finish, despite being reduced to 11 men by fulltime through two sinbinnings.
Boxon second rower Jordan Davis was one of the Mustangs' try scorers, with clubmates Pene Turia-Bennett and Che Barlow also in the team.
As a result of their win, the Taranaki Sharks will host the seven-match New Zealand Cup competition starting this month, and will be the Central Vipers squad to represent the region.