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There is no "official" limit, but I know for a fact that Chi O, KD, and DG (possibly the others I just only personally know about these 3) will take absolutely no more than 5 MAYBE 6 girls from one high school in a year. And those are the just the largest high schools like Madison Central, Oak Grove, Tupelo High, etc. Normally there are no more than 3 or so girls from certain schools, especially Jackson and the Delta private schools, because there are a ton of those schools and girls rushing. You don't want to be known as the sorority with mostly girls from the exact same area. So the best of those girls are normally split evenly between those houses.

Phi mu took 6 from one of the largest schools. They cut anyone with a HS GPA below 3.2 right off the bat.

The chances of a sorority wanting 10 girls from the same high school is very slim. Those 10 girls would all have to haves 4.0 GPA, tons of activities and honors, and outstanding personalities in order for that to happen!