Imo both fighters should forget about fighting Carl Froch, and concentrate on what would be a very good domestic clash.
Froch has his heart set on a big fight in Vegas and rightly so.
In the fist fight between De Gale and Groves, it was very close, and some people think that De Gale won. Since then, Groves has had big setbacks with beatings against Froch that will have knocked his confidence, and his recent victories were not against world class opponents.
On the other hand, De Gale who is now reportedly injury free has improved considerably both physically and mentally. My money would be on a De Gale victory, although it would be close and a true British classic.