I would love to have 2 different settings for dimming my monitors.

I already use the dim function set at 100% to dim everything unneccesary when e.g. watching a movie on my projector (my monitor doesnt use backlight and turns itself off when the input is pure black). But in the evening I like to watch youtube on one montitor and play games on the other and i'd like to turn down the light of the 2nd monitor.

Is there a way to have a script for dimming at e.g. 50% all other monitors?

Thanks for your Help
Cheers Suat