Whenever it is enough for one member of a group to succeed, e.g. in a Knowledge check, only the character with the best total score rolls. The benefit (or detriment) for working as a group is represented by a simple modifier, usually +1. If that modifier makes the difference, it is explained by the group coming up with the solution, otherwise the character who rolls.
Likewise, if all members of a group must succeed, e.g. in a Stealth check, only the character with the worst total score rolls, and the added risk of being a group is represented by a penalty, usually -1.
Adventure modules from other popular games often use the concept of Saving Throws, which are easily imported.
They can be very flexible and usually follow the formula:
[DR + Virtue + Expertise OR Lvl//2 - Difficulty].
Awareness checks are typically Group Checks for
[Finesse + Survival] or [Finesse + Stealth] or some other Expertise,
depending on the situation, minus a Difficulty.
Often it is preferable if the players don't know there is a check. In that case, just assume a DR of 0, or roll secretly.
To check for traps, spend 1 CA or 10 minutes and roll secretly:
Checking Result = SECRET DR
+ Finesse
+ Stealth
- Difficulty
- 2 if not spending 10 minutes
Result Effect
< 0 "No traps"
= 0 Something seems off, may roll again
(even if there are no traps)
1-3 Found the trap if there is one,
but possibly missing something
4+ Found everything there is to know