Select how many samples / material individually in cycles.

I would love the feature where I could select the maximum amount of samples in cycles for every object / material individually , because it is very common that some materials are more noisy than other and will be good only with a lot more samples, but if some objects are good even with 100 samples, it would be ridiculous to render them all with 5000 samples.

In other hand it would also work with selecting the sampling amount to objects. so now if i have in my animation some important object that I know it will be in the focus, I could render it with slightly more samples than the background that is not so much in the focus of viewers.

I don't know how this would work with caustics / bokeh etc, that causes noise to other surfaces, but maybe it could be figured out somehow?