Animosity between the two fighters is not helping the process as Groves seeks revenge following his controversial ninth-round defeat by the WBA/IBF super-middleweight champion last year.
Many felt Groves was unfairly stopped by referee Howard Foster after having floored Froch early on and dominated much of the fight.
The IBF agreed, ordering a rematch between the British pair, but Hearn confirmed they are still some way from agreeing the clash.
He said yesterday: “We’re still going. I think purse bids will be called this week and it will take 28 days until they happen. During that time you can still negotiate.
“It’s frustrating. Earlier this week it felt like we were quite close and then it was not so close a few hours later.
“I’m still hopeful we can get there, as I have been from the start.
“Both fighters have probably got to loosen their belts a little bit and then hopefully we can get there.”
Hearn added: “It would be a crime for it not to happen but I believe it will.
“As the promoter I have to look at all the options for Carl Froch, including Julio Cesar Chavez Jr and Gennady Golovkin as potential opponents .
“But, ultimately, this is the biggest fight out there, I’ve said that from day one.
“The IBF’s decision to call for the rematch both helped and hindered the possibility of the fight. It helped because Carl doesn’t want to vacate his IBF belt really, so he probably will fight George.
“But it hindered because they ordered the purse bids with an 85%-15% split, which ultimately lowers George’s bargaining position, which doesn’t really work that well in negotiations between two people who don’t particularly like each other.”