Depends on what kind of help you mean. I'm a simplicity first kinda GM, so, when people want to help each other I generally reduce the difficulty. For example; a party needs to roll a boulder out of the way. The Boulder is a Very Hard action to move. Jeremy is the strongest with a +25 STR so he is going to make the roll; while tara & dean help him they have a combined STR of +30. I would say that a +30 would reduce the difficulty by 1 degree & Jeremy can roll a Hard Action.