strategy to divide the class of large number of students
Typically, in the US, large classes are divided into sections and scheduled at different times throughout the day. Then the students pick which one best fits their overall schedule when they register. Registration times are typically done by class, nominally seniors, juniors, sophomores, and freshmen, with a later period nearer to the start of the semester to give students some time to rearrange. The enrollment in each section is capped, and students may fail to register for their preferred time, but that's just how it is. 

Typically undergraduate students are not divided up into sections by grades, but there may be entirely separate classes organized for students that are on some sort of Honors track. Good grades and other things are required to get into the Honors track, but after that, there's little use of their grades to separate them from non-honors students.