I am finishing a bonus room. We ran 2 16g runs down to the electrical box. Each one will have about 4 outlets on it. Question has to do with the ground wire. We can easily wire the blacks to gold and whites to silver, but when it comes to the grounds and the small green screw, we are having trouble. Is it necessary to get both grounds around that green screw, or can we just wire nut together and screw the last one in the last outlet?