Australia prop Scott Sio says there's no chance of the Wallabies and New Zealand ever collaborating for an opposed scrum session the way England and Wales have.
The two old northern hemisphere rivals enjoyed a 40-minute hit-out on Monday that featured 12 scrums and 16 line-outs under the scrutiny of top international referee Nigel Owens in Bristol.
The idea was put forward by England coach Eddie Jones to his Welsh counterpart Warren Gatland ahead of their teams' encounters with Argentina and Australia respectively on Saturday.
Sio admitted he'd be intrigued by the prospect of a similar hook-up with the All Blacks but couldn't envisage Wallabies coach Michael Cheika ever picking up the phone to Steve Hansen or any other international coach.
"We'd learn a lot but I don't think 'Cheik' would allow it even if we weren't playing them that weekend," Sio said.
"They (Wales) have had a really strong system here for a while now and it's just them trying something new to see if it can improve their game.
"They are a very set piece-focused team and we know we're in for a battle."
Cheika lost his scrum coach Mario Ledesma last month after the former Pumas prop moved home to Argentina to take up the top job at Super Rugby franchise Jaguares.
A replacement won't be announced until after the spring tour, but Sio said Ledesma's influence lives on among the front-rowers
"I think he's laid a great foundation for us that I think we can keep building on," Sio said.
"I guess not having him here has put a lot of focus on the players to step up and really demand a lot from each other at the set piece.
"We've definitely lost his presence but I think a lot of the passion has rubbed off on the players."
After a difficult year for Australian rugby, Sio believes there is some light at the end of the tunnel after the win over New Zealand last month was followed up by the 33-point victory over Japan on Saturday.
"Any time you beat the best team in the world it's definitely going to raise the attitude of the team and keep the spirits going," he said.
"We took what we could from that game, what we did well and what we needed to improve, and tried to bring it to the Japan game.
"We didn't start the rugby championship the way we wanted but we improved as every game came along which is the thing about the growth of this team."
Wales lock Jake Ball, who spent his teenage years in Perth after his family moved to Australia, admitted the sessions with England did contain some extra edge.
"I thought it was a good battle, and we got something out of it," Ball, a former WA U19 fast bowler, said.
"We had some really good scrums and were happy with our lineout as well.
"When you train against each other week in, week out, everyone finds out what are your weaknesses, so it was nice to go up against an England pack you didn't know too much about.
"It's got added edge because it's against England. You want to put your right foot forward yourself as a player."
