How to set different gravity scales to each collision bodies in Physic asset editor?

I tried to make hair movement simulation by Physic asset editor in UE4. I got satisfactory result when I used Grav Scale to 0.5. I used gravity scale as air resisance. But I set it to 0.5, other parts’ movement simulations were broken. So, I changed mass scale in collision body of hairs to 0.5, there were no difference what I recognizable.

In short, my question is this. Is there a way to set gravity scale to each collision bodies differently?