Access Mipmap texture from Render Target via Blueprint

Is there a way to access a mipmap texture produced by a scene capture component via blueprint? I would like to take an average color sample from captured scene, but i can only access the full resolution render target.
I am using a 20x20 render target with 5 mipmaps to have a mipmap with 1x1. I would like to read the color value from this mipmap via blueprint, is there some way of doing this or another more clean and efficient way of doing it ?
In Material Editor i successfully forced a material to use the mipmap, but not in a blueprint.

Tks