Mass photo editing, increase value by a certain amount rather than setting it

Hi,

I selected 10 photos and I want to increase a value such as highlights or blacks for all of those photos by a specific number. I do not want to set it to a given number, as this will change all photos to same value. The photos already have different values and I need each of this values individually to be adjusted. I am looking for an option like in Library Mode - Quick Develop.

How do I do this ? 🙂