He said they had decided to involve a few others who had similar values and shared their passion for the sport.
"We will compete as individuals but we will support each other, hang out together," he said.
Leishman, 33, is one of the top contenders for the mens' triathlon, in a field that includes three of last year's top four finishers. The mountain bike specialist has competed in seven XTERRA Rotorua triathlons, making the podium five times.
"I am probably the fastest Kiwi never to win it," he said.
"It would be nice to complete the set of medals with a gold."
A motocross accident in November meant Leishman missed two months of training with a snapped forearm, so tomorrow marks his comeback.
"I am strong but I am feeling like if it was another three to four weeks I would be fine," he said. "But I've still got a shot."
Leishman said the favourite for the race would have to be Australian Ben Allen.
"It's his race to lose. He's a full-time pro, well-prepared and got some form," he said.
Scott Thorne (Hamilton) is another Kiwi expected to challenge for the title, while Leishman tipped "freakishly good" half ironman Graham O'Grady (Taupo) as a possible dark horse in his first XTERRA event.
In the women's event New Zealand and Oceania mountain bike champion Leary is also on the comeback trail after 15 months of illness and injury.
The 28-year-old won the event in 2009 and 2010 but tomorrow will be her first real test since returning to fitness.
In what could be a "battle of the couples" Allen's girlfriend Jacqui Slack (Australia) is shaping up as Leary's main competition, along with Renata Bucher (Switzerland).
Leishman said the atmosphere was what made the XTERRA Rotorua Festival such a great day out.
"It's so many people from so many different sporting backgrounds coming together," he said. "There's an energy about the thing."
The 11km and 21km trail runs and walks start at 8am, the 26km mountain bike event at 9am and the XTERRA team and individual triathlon from 11am.
