I want my lighting set up so that at night my HID driving lights go on and off with the high beam and my XLO fox/conspicuity lights go on and off with the low beam. For fog and daytime I want just the XLOs to go on with the low beam. The solution was to add a diode between the ground triggers for their relays.
Like so:
(http://i1221.photobucket.com/albums/dd470/Motobrick/auxlights/K75F_XLO_HID_Diode_Aux_Light_Wiring.jpg)
Here's the diode with wires soldered to it:
(http://i1221.photobucket.com/albums/dd470/Motobrick/auxlights/HID_XLO_Diode.jpg)
Of course that's probably not going to hold up very well so I entomb it in a piece of plastic straw filled with epoxy. Much more durable and waterproof:
(http://i1221.photobucket.com/albums/dd470/Motobrick/auxlights/Diode_Epoxy_Straw.jpg)