[Nieboh]

You should double check your state's laws regarding the use of multiple beams. In most states, fog lamps and high beams are considered the same, and you are limited to 4 filaments burning at once. It will be illegal in most states to operate fog lights while also operating high beams. Also, what would be the point? Unless your fog lights are obnoxiously bright, you really won't even see them with your high beams going. If conditions are such that you need fog lights, high beams will reflect back in your face from the fog, snow, etc. that necessitates the fog lights, making visibility worse. Other than to be a jerk (and there are plenty of times when I'd like that feature to 'get back' at trucks with fog lights as bright as regular lamps) I don't know why you would want this.

By example, this is from an Oregon Department of Transportation safety release:

Fog lights are designed to be used at low speeds in fog, heavy mist, snow and other situations where visibility is significantly reduced. Front fog lights are generally aimed and mounted low to increase the illumination directed towards the road surface. However, after sunset and during other low visibility situations, fog lights are required to be turned off when an oncoming vehicle approaches. During normal visibility conditions, fog or auxiliary lights should be turned off. It is not appropriate to drive with fog or auxiliary lights left on all the time

From Washington State vehicle codes, they're a little less clear on the issue:

RCW 46.37.230Use of multiple-beam road-lighting equipment.
(1) Whenever a motor vehicle is being operated on a roadway or shoulder adjacent thereto during the times specified in RCW 46.37.020, the driver shall use a distribution of light, or composite beam, directed high enough and of sufficient intensity to reveal persons and vehicles at a safe distance in advance of the vehicle, subject to the following requirements and limitations:
2) Whenever a driver of a vehicle approaches an oncoming vehicle within five hundred feet, such driver shall use a distribution of light, or composite beam, so aimed that the glaring rays are not projected into the eyes of the oncoming driver. The lowermost distribution of light, or composite beam, specified in RCW 46.37.220(2) shall be deemed to avoid glare at all times, regardless of road contour and loading.
(3) Whenever the driver of a vehicle approaches another vehicle from the rear within three hundred feet such driver shall use a distribution of light permissible under this chapter other than the uppermost distribution of light specified in RCW 46.37.220(1).