Make rigidbodies use my own custom timescale?

I have a custom timescale to do slow mo for some objects but not all of them. In simple it is something like this

timescale = 1 * Time.deltaTime;

What I don't know is how to make my rigidbodies use this custom timescale instead of the default one?

You could adjust Fixed Timestep in the Time Manager or fixedDeltaTime by script.