Custom Assessment Times by Class

I know that I can add custom start and end dates for assignments and assessments, however, I have to assign to one class at a time to enter the start/end individually. On the page, when creating the assignments, where I can select each class I want to assign the item to, THAT would be an optimum place to add the custom start/end times to each class. Maybe a toggle asking if we need individual start/end times as well. Then we can have the option to customize as a whole to ALL classes as one or change the selection to individually and set things by class period.