Which definitely works, but is a bit more abstract than I would prefer. A group check on stealth assumes that the characters with the higher Dexterity (Stealth) bonuses are skilled enough at moving stealthily that they are able to help the characters with lower modifiers out it and hand waves the specific details of how they do it. And there’s nothing wrong with that necessarily, but personally I prefer to get a bit more specific than that on what the characters are doing to help. That’s why I prefer to have the character with the lowest modifier roll, and if the other players want to help mitigate that character’s weakness, they can describe specific goal-and-approach actions they take to do so. It’s still somwhat abstracted, as we’re only focusing on what the characters do to shore up their weakest link and hand waving everything else. But that added bit of specificity, for me, helps keep the world from disappearing into the abstraction, and also cuts down on the number of checks that need to be rolled to resolve the group action.The premise is that they're working together to achieve a better result than they would if each of them made the attempt unsupported, the more proficient providing assistance to those who are less skilled. Thus, the successes of some compensate for the failures of others.