They have to have a seven or higher in any skill to get into The Academie, plus at least two scholarships (preferably the Scholar's Grant AND one of the skill-based scholarships). The Academie stresses on a focus of a specialized area. They don't want sims who don't know what they want to do with their lives. If a Sim changes Major's more than twice, they have to transfer to Sim State or La Fiesta. They don't technically have a 'Greek System' but ever since Delilah Cosgrove attended, she founded the R. Cosgrove Scholarship House for Women and it more or less works like a classy sorority.

Sim State requires the Scholar's Grant and at least 2 points of every skill. Sim State wants a good rounded base of sims that will work hard on their studies. They support students wanting to try different majors before senior year. However, if anyone goes on academic probation more than twice while there, they must transfer to La Fiesta or drop out. They have a thriving Greek Scene.

La Fiesta will take anybody with a Scholar's Grant, skill level doesn't matter. The theory is there that they can learn and everyone deserves a chance!

I only use Sim State for i like how it is set up.

Only time I use the other 2 is when I make a clean and empty hood and then attach all 3 to it and play the students untill they all graduate and they become the Sims I will play in my main hood.

I haven't really played Greek houses much, except in my megahood the Capps founded one for all future Capps to pass through. It means they get an easy ride, with all of those pledges to do their work, the good/expensive skilling objects, and high value need fulfilling items like beds, too. They often find their future spouse at the "Capp Domus" too - any sim privileged enough to get in has the necessary education, class and social skills to marry into the Capp family.