Possible Clues:

• Group of US colleges with prestigious reputations
• Lions, Tigers and Bears play in it
• Prestigious octet
• Is driven up the wall by Union in American schools
• Quakers play in it
• Northeastern educational octet ... or, in a way, what the ends of 20-, 31-, 49- and 61-Across comprise
• Name given to eight eastern US universities of particular academic and social prestige
• Penn station?
• Top US universities
• Like some educations