Beijing looks like it has a very well laid out airport.
Do your departures normally depart from the closest runway to their parking or is it based on direction of flight?
Do you arrive and depart on all three runways (mixed-mode) at the same time?
There is no way of ensuring that aircraft in different wind conditions remain separated other than provide more than the minimum divergence on departure. I would think that aircraft on RNAV departures would have accurate enough track keeping that they would not be an issue. Non-RNAV departures would need vectoring to ensure separation.