So the requirements of this trophy mean you have to have 3 other people present so that you can put a mask on them all 4 of you at the same time. However, if you are like me then it might be hard to get a couple of people together. Luckily you can trick the PS4's camera into thinking there are other people present. You can use photo's, DVD covers, figurines as long as there is a clear face the game will think it's another person. Once you've assembled your 'friends' simply put a mask on all 4 of you and the trophy will pop.