I didn't know that the Taigen board did this. I added a convoy light to my PzIII and ran it in parallel with the headlights. It stays on all the time. I did that because the convoy lights are on the upper hull with the headlights and I didn't have the tailight plug (it's smaller than the other two-pin plugs). So, I guess I accidentally avoided your challenge.

From your description, I guessing that is a feature that is hard-wired. So, you're best bet is to rewire them in parallel with the headlights.