What you want to do is have the rear turn signals also be run/brake lights.
The
<u>Kuryakyn</u> adapter allows you do use your stock single filament bulbs for this, just replacing the lenses with red lenses to be legal.
As far as I can see they do not make an adapter for dual filament turn signals.
The wiring of the dual filament bulbs is easy, to a point. You can wire the high wattage lead to the turn signal and the low wattage lead to the taillight and you will have turn signal and running lights. But not brake. You can tie the brake light in by using power diodes to isolate the lamp from the leads so that voltage will not feed back -- a basic OR circuit. The bright light will flash with the brake or the turn signal. But...... the brake will override the turn signal's off time and you lose the turn signal when braking.
To get what you want you need an EOR circuit -- an exclusive or. The lamp will light with the turn signal or the brake, but not both -- so the lamp will flash off when the turn and brake leads are hot. You need transistor switches -- a bit more complicated than just connecting up a diode. Not something I can help you with. Fortunately....
Trailers run dual filament turn/stop/run lights and connect to cars with separate stop/run and turn signals.
<u>Draw-Tite</u> makes an adapter that could be used to do what you want. While I haven't seen or done one, it should work just fine. Follow the instructions that come with the module and to attach to your brake/run/turn leads, use the trailer output for your dual filament turn signals.
I may be a total loss with it comes to wrenching, but electricity and I are old friends.