Adding cars onto the left side of a road using Generative Fill

I need to retouch a drone image of an empty road to add cars. Generative Fill does a believable job, but only if I do one at a time – I can’t select a section of road and ask to add multiple cars at once. That’s okay, I’m happy to do them one-by-one, however a major problem is PS will ALWAYS point the cars in the wrong direction for Australian driving conditions, with RHDrive cars that drive on the left side of the road. In this case, it’s not simply a case of doing a horizontal flip to mirror the image. I’ve tried a number of ways to specify the prompt, e.g. ‘white car driving towards the left edge of the image’, or ‘white car driving on left hand side of road’ or ‘white car driving on road in Australia with tail lights visible’. PS refuses to do it. When I use ‘… headlights visible’ or ‘… tail lights visible’ … it will put headlights or tail lights on the front and the back of the car.

Any help here most appreciated – I have many photos to update in the same manner and it will be a very tedious process doing them one-by-one and then need to retouch the car’s lights or create the car on the ‘wrong’ side of the road then move to ‘right’ side of the road and adjust the lighting to blend it into the road.