I've been working on a car recently which has 4WS/AWS (well actually AHK). Is this currently possible in rFactor 2?
I've never tried linking the steering arms to the rear suspension. Try it and see what happens. But as far as actual support for it, and conditional activation or variable rates (apart from a possible chassis adjustment changing the link points, assuming joining to the rear does work) the answer is no. *this method, if it doesn't crash the game or simply malfunction, would probably also exclude using chassis flex.
Thanks @Lazza It seems BMW used an odd system which actually steered the wheels in the same direction as the front wheels to aid stability at high speed. This made use of some clever electronics which I guess would be impossible to simulate. Also, it was replaced by Dynamic Stability Control which did a similar job - at the cost of perfomance - for a cheaper price. I'll try to bodge it by linking the steering arms and see what happens. I'm imagining some amusing results!