Shadow catcher, possible ? Oo

The only thing you could do right now is a custom per object shadow. by default the shadows would be crisp and they will only really work from point or directional lights. you would have to write a custom blurring shader to blur the result.

details about this method can be found at my blog here:

http://shaderbits.com/blog/custom-per-object-shadowmaps-using-blueprints

There is no standard feature but you can build what you need using this.