Premiership Rugby chairman Quentin Smith says there has been plenty of interest from PRO12 clubs in the proposed Rugby Champions Cup.
Both Premiership Rugby (PRL) and their French counterparts (Ligue Nationale de Rugby) remain insistent that they will not return to the negotiating table to discuss the Heineken Cup.
Instead, both bodies will aim to press on with the newly-formed tournament, despite European Rugby Cup (ERC)'s belief a compromise can be reached, arranging a meeting for stakeholders on October 23.
As it stands, all four unions representing the nations that make up the PRO12 (Scotland, Ireland, Wales and Italy) have released statements confirming their clubs will not take part in any cross-border competition without the approval of the International Rugby Board (IRB).
However, Smith believes that the clubs themselves are weighing up the possibility of joining the breakaway versus allegiance with their respective unions.
"We've opened the doors to everyone else in Europe," Smith told the BBC.
"There is a lot of interest and frankly we're not surprised. We've had discussions with all sorts of people.
"What's difficult for everyone else is that any other team that is talking to us or would like to join is having to have difficult conversations with respective unions. Each of the unions issued a press release and made it abundantly clear that no team could participate without their blessing."
More will become clear, the chairman says, after Wednesday's meeting has taken place, though he confirms the English and French stakeholders will not be in attendance.
"We know that everyone else is having those conversations. It's unlikely we will know exactly where anyone is until later this month. There was a meeting called by European Rugby Club for next week, October 23. We're [the English clubs] not going and the French clubs aren't going," said Smith.
"But there's a good chance that others will go and I suspect nobody will want to, for want of a better term, break cover before they've been through that meeting."