So what is your request? If it's about denoising that would take the same amount of time, no matter how many REs you have, then i think that's not possible, otherwise Corona team would done it already - you don't think that they made denoising for each RE to take its time just for fun, don't you? On the other hand, if you want only beauty to be denoised and no REs, then simply turn off "apply denoising to this render element" option in each RE.