It has long been expected that Payne, who will graduate with GR to Supercars next season, would make his main game debut alongside Reynolds, while Campbell would partner Holdsworth.
However the squad has confirmed that the factory Porsche ace will instead share the lead entry with Reynolds and Payne will be paired with Holdsworth.
“I’m very excited to be co-driving with Dave this year for Penrite Racing," said prototype-bound Campbell.
"He has won the race before and is always quick at Mount Panorama, so I just want to help put him in the best position possible to be at the pointy end late in the race and pay back the Groves for this opportunity.
“Bathurst is a race that carries so much credibility overseas. Winning the 12 Hour was a real highlight but winning the 1000 is something I’d really love to achieve in my career.”
Payne, meanwhile, will be partnering veteran Holdsworth, who he is set to replace in the #10 Grove Racing Mustang next season.
Holdsworth is widely expected to move to Blanchard Racing Team as a replacement for PremiAir-bound Tim Slade.
“Racing in the Bathurst 1000 has been a dream of mine since I started racing karts in New Zealand," said Payne.
"It will be a big weekend doubling up with Super2 as well. I look forward to doing the best I can and working with Lee to do a solid job for Penrite Racing.”
Team Principal David Cauchi added: “Campbell and Payne are going to be a great mix of experience and youth. Campbell has won many endurance races including the Bathurst 12 Hour, and he competes in endurance racing all the time so the team can draw on his vast experience.
“Payne has done a great job for us in Super2, proving that he is not only fast but can manage his raw speed over a race distance. Going to the Mountain for the first time as a main series co-driver is a big undertaking, so pairing him with the man who won the race last year as a co-driver is the perfect match.
“There are a lot of points on offer at Bathurst and it is a long day in the office. It is all about minimising mistakes from everyone and being on the lead lap for those final stints to the chequered flag. If we can do this, anything is possible from there.”
Payne will cut laps in Holdsworth's car during the dedicated co-driver session at Sandown on Friday, while Campbell is currently overseas.