What would you do: Feuding employees threaten project's success

Periodically, we ask three HR managers how they’d handle a difficult situation at work.  Today’s problem: The company has an important project that needs the cooperation of two feuding employees.
The scene:
Charlene Silvera almost knocked over HR manager Rob Jenner as they passed in the hallway.
“Oh, sorry, Rob,” Charlene apologized. “I guess my mind was somewhere else.”
“Everything OK?” Rob asked.
“I’ll live,” Charlene smiled. “Although I’m not sure I can live through another meeting with Ed Lopat and Joe Cronin.”
“I guess those two still don’t get along,” Rob surmised.
“Like oil and water,” Charlene said. “I’d love to be able to separate them, but their cooperation is absolutely crucial to the success of our project. And managing those two is becoming a fulltime job.”
“They don’t have problems working with others, do they?” Rob asked.
“No, just with each other,” Charlene noted. “For some reason, you can count on the two of them getting into an argument during a meeting. You can just feel it coming.”
The blame-game
“How about discussing it with them?” Rob suggested.
“I tried that to get to the bottom of the problem,” she explained. “All I got from the both of them was a blame-game – ‘he did this, and he did that.’”
“Is there some way I can help?” Rob said.
“You don’t happen to have a whip and a chair, do you?” she joked. “But, honestly, at this point I’m open to anything.”
If you were Rob, what would you suggest to Charlene to end the feud between Ed and Joe?
Gary Lane, HR manager, Barnstable, MA
What Gary would do: If their full cooperation is crucial to the completion of the project, make that part of their performance standards. And give the manager the authority to make the judgment call on whether they are cooperating – and meeting the standards.
Reason: You have to put the problem in terms that are real and immediate: “You’re required to meet this standard, and failure to do so will be harmful to your success here.” That should get their attention. Or, if it doesn’t, they know they’ll suffer for it.
Tom Petersen, program manager, Eagle River, AK
What Tom would do: Through meetings and exchanging ideas, I’d explore all the possible fixes, but you may want to consider the possibility of just living with the situation. If, in the end, they produce, even though they’re high maintenance for the manager, that could be acceptable.
Reason: Nothing’s perfect, so you have to decide how much “imperfection” you’re willing to live with. It probably wouldn’t hurt to somehow show some appreciation for the manager and what she’s doing to get the two of them to work together.
Michelle Grovner, HR representative, Brunswick, GA
What Michelle would do: This could be a situation that calls for training. Neither person seems willing to take some responsibility or recognize the cause of the problem. That means they probably need some guidance on recognizing their own problems and changing their behavior.
Reason: Sometimes we’ve seen that people are totally unaware of the fact that they’re causing problems. The possible solution is to make them aware and teach them how to change.