You can use a Script operator to measure their distance to target and then send out in order over time.
Keep in mind a particle target is a particle ID, not a simulation index, so if your IDs don't match your simulation indices you'll have to do a bit of bookkeeping in your script to match them up. You can check if they match using a Display Data operator.
Keep in mind a particle target is a particle ID, not a simulation index, so if your IDs don't match your simulation indices you'll have to do a bit of bookkeeping in your script to match them up. You can check if they match using a Display Data operator.