Well, this has been an interesting thread, and I've learned much. In South Africa, I had my scut hives fairly close together because of the need to have them raised,(some of the ants can be meaner that the bees) and when drifting occured, there wasn't the gentle tugging that I see here in Ca., but intense homicide (apicide?). My best results were to make several marks of different shapes, and of different numbers and on different parts of the hives, which were all white. So, there would be an "X" (all markings in black) right in the middle, and next to it 3 solid circles spread in a line on the top. Next to this, Two big squares, one on the upper right, the second on the lower left, and so on and on. This eliminated the fighting literally in one day.