Blur specific gameobject

I have been taking a look in Camera's, layers and post-processing layers / volumes. What I would like to achieve is for example a scene with 5 cubes out of which one is blurred (like censored -> unable to recognize it). What I managaged to get so far was to have a specific camera `BlurredCamera` with as a child A post-processing volumne that applies a depth-of-field effect. But this eventually blurs everything BUT the gameobject. How could I blur a specific gameObject (e.g. by setting it to a specific 'Blurred' layer)?