I tried to hook one ballast to the lowbeam and the other to the opposite side highbeam. When I go from low beam (left light on only) to high beam (both should be on) the left goes of and the right comes on. Not what I wanted. Lowbeam one light on, high beam both on.
Sounds like you could use a relay then.
Standard 30amp/40amp automotive relay like so: http://www.amazon.com/Absolute-RLS125-12-VCD-Automotive-Relay/dp/B0002KR9GG/ref=sr_1_1?ie=UTF8&qid=1352070159&sr=8-1&keywords=relay
Would wire it like:
Pin 87 to positive battery terminal +12v (with 15amp in-line fuse).
Pin 87a to low beam positive wire.
Pin 30 to HID ballast positive wire (low beam side).
Pin 86 to high beam positive wire (in addition to the high beam HID positive wire).
Pin 85 to ground (either battery -, frame ground or black/ground headlight wire).
Make sure that the low beam HID ballast positive wire is ONLY connected to pin 30, no other wires.
Now, when you switch on high beam the low beam HID will switch to the battery for power, instead of the low beam wires which no longer have power.