driving light with drl

I have an '04 Chevy Blazer. I'm trying to hook up a set of Hella 500 driving lights to come on with the high beams, go off with the low beams and stay off when the daytime running lights are on. The daytime running lights actually use the high beam bulb at a lower voltage. This throws a wrench into the idea of wiring the signal lead from the driving lights relay into the high beam harness. It triggers the relay to turn on the driving lights with the daytime running lights. Is there a special relay available that will only trigger with a full 12 volts for the high beams and not the 5-7 volts that the daytime running lights use or is there a better way to accomplish the same thing? Thanks for any help.