Getting variation in angle of motion for bullet behaviour

Basically, I have it where a ball (via bullet) follows the same angle of motion when bouncing off another object. Even if the ball hits a different side of the object. I still want the angle of motion to follow the same kind of arc (for gameplay purposes) but I want to introduce some slight variation (by 5 degrees) into the angle of motion if the ball hits specific areas of the object. Like this:

Can this be done in bullet behaviour? Perhaps by calling different image points (but what should I bring up in the event panel to do that)?

EDIT: Forgot to add it, but imagine there being a bounding box around the object. So, dead center bounces out at 285, from the center to the top left at 280 and on the entire left side at 275.

if you already have the bounce done, and simply want to "add variation", try:

set angle: Self.Angle + choose(-5,-4,-3,-2,-1,0,1,2,3,4,5)

It will randomly pick one of the values from choose and will add/withdraw