I think left to right, it's NORMALLY: single, group, group, group, group, single, ski school. The two left groups alternate and pick up singles from the left. The two right groups alternate and pick up singles from the right, then those "collated" lines alternate again before the chair. Works fine. Especially when Dennise is there.
Occasionally, the middle group lines might be a total of six, which doesn't work quite as smoothly. Especially if some liftie has to leave for a bit.