Istyer, for that, I let people do "Group Checks" (for things like Perception, Survival, etc.) If everyone is actively trying to do something (watching for traps or searching an appartment for clues, or building a shelter, finding food, etc.) then I'll take the highest Skill and the highest linked stat across the group (like skilled aid in RAW) and then add one Boost die for each other person helping (like unskilled aid in RAW). It is much easier than having each individual person roll it, and it allows you to make more daunting tasks and challenges for the party while still allowing them to succeed by working together.
For Stealth, I might say that the sneakiest guy and the most agile guy lead the pack, pointing out rocks and other mayhem that might ruin their cover. I'll also probably add setback dice when needed, like if the other two members are wearing heavy armor or are huge, lumbering and clumsy gammoreans. If multiple people can do it, I like having everyone work together as a team. It makes for a good time. You can do this for just about anything that you or your players can spin, like lifting rocks or collectively cheating at cards to swindle one dude for money (ala 21.)
Edited by Endrik Tenebris