Nobody answer but I get a solution:
I created a blueprint, placed a unit size box on the origin, and set this to inherit from a created class that I called InteractiveComponent. Then I use this blueprint as a child component on others blueprints that I want to interact with some parts of them. After this, I can cast the object that was hit by trace to InteractiveComponent and if the cast has success I do the interaction. If the interaction have an animation (my case) I have to set the socket of the InteractiveComponent to the parent bone of the animation.