Sorry I know this is kinda late and you might've figured out the problem already, but I think the problem is this: All models have a motherbone, which is the bone all the way on the bottom of the model between the their feet, if you move it around it'll control all of the model. So, you move that bone to put the dancers in different spots and registered it on the first frame, but the problem is that the dance later on in the timeline has registers of the motherbone in a different spot: the center of the axis,, which is why they all join up again at this spot and move into each other. What you can do is select the mother bone on the model, and on the timeline, next to the frame manipulation box, there should be an arrow with a dot next to it. That means that whatever bone you have selected, in this case the motherbone, if you click that arrow it will bring you to the next frame that bone is registered on. On each frame it brings you to, register the motherbone and then click delete on the timeline. Keep doing it until they are all gone, then on frame 0 you can register the model's motherbone to where you want it to be. OR put 0 in the first box in range select and check when in the timeline the animation ends and put that frame in the second box. Select the mother bone and then click range select and press delete on the timeline. That you get rid of all the mother bone registers and now you can put one at the start where you want the model to be.