When the party works together toward a common goal, the Judge can call for a group check and determines which skill is appropriate and how many characters can reasonably participate. Each participant makes a simple check. If half or more succeed, the group check succeeds. Otherwise, it fails.
You cannot enter a devil's bargain during group checks, as they rely on collective, rather than individual skill.
During exploration, you might find ways to pool your efforts into a group check. For example, each character leaping across a chasm would make an individual check, while four character's working in unison to lift the stone lid from a massive sarcophagus would make a group check.
Outside of exploration, the party makes group checks for two things: retreat and room traps.
When the party makes a decision to retreat in combat, make a group check using Grace, escaping on a success. The full rules are found in the encounter chapter.
When the party triggers a room trap, they make a group check. On a success, they spot the trap in time. On a failure, the character with the lowest result springs the trap and suffers the effect.