The English clubs' chief negotiator, Bruce Craig, the chairman-owner of Bath and PRL vice-chairman, who has been the go-between with Paul Goze and Ren Fonts of the French Top 14, is confident they will all accept.
The RFU has said publicly it is waiting for detail of the new competition before deciding whether to give its blessing, which would be necessary under international rugby regulations.
But Peter Boyle, an IRFU representative on the Heineken Cup's organising company, European Rugby Cup (ERC), countered both the RFU stance and a report that three-times European champions Leinster might join the new competition.
Boyle said: "The RFU and French Rugby Federation have already confirmed that there will be no new company other than ERC to run European competitions. It is unequivocal that the negotiation of TV and other rights is central and it's done by ERC.
"The IRFU are bound into ERC and that restricts completely the movement of Leinster, Munster, Ulster and Connacht."
Boyle also fiercely rebutted PRL's claims of Celtic intransigence. He said Ireland were prepared to give ground on the subject of meritocratic qualification and reducing the Heineken Cup from 24 teams to 20.
ERC announced on Saturday that a Canadian independent mediator, Graeme Mew, had been engaged to try to bring all the interested parties together.
- Independent