I will nominate Commencement by J. Courtney Sullivan.

From Publishers Weekly
It isn't quite love at first sight when Celia, Sally, Bree and April meet as first-year hall mates at Smith College in the late 1990s. Sally, whose mother has just died, is too steeped in grief to think about making new friends, and April's radical politics rub against Celia and Bree's more conventional leanings. But as the girls try out their first days of independence together, the group forms an intense bond that grows stronger throughout their college years and is put to the test after graduation. Even as the young women try to support each other through the trials of their early twenties, various milestones—Sally's engagement, Bree's anomalous girlfriend, April's activist career—only seem to breed disagreement. Things come to a head the night before Sally's wedding, when an argument leaves the friends seething and silent; but before long, the women begin to suspect that life without one another might be harder than they thought. Sullivan's novel quickly endears the reader to her cast, though the book never achieves the heft Sullivan seems to be striving for. (June)
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http://www.amazon.com/Commencement-V...N57J9QXNQNPWCW