Canon DPP – how to adjust brightness to specified maximum level on some spot automatically

How to adjust brightness to specified maximum level on some spot automatically – for example – on some spot I want to make brightness not exceeding RGB (250,250,250). I can adjust brightness manually by looking at RGB values at bottom bar – but it’s time consuming. Is it possible to do it automatically – by clicking some spot on photo (of course by saving some property before of 250,250,250 – maximum brightness)? Would be nice to have an option to do it automatically at the same time when adjusting/clicking white balance on some spot.