try this, make a custom switch and insert the switch sensor position in the wires that run to your corner lamps (just like how you sliced them off for then Nostril Nozzle washers or whatever), and mount a switch near you light control, kinda like an alarm switch; so you can manually switch it off when your headlamp is on. Just like a manual fog light control. Of course, the corners WON'T be off when the headlamp is ON by the 2nd click UNLESS you throw the custom switch and set the corners off.

Need some resistors for them to work. It'll cost you 5 bucks max.