The chandelier-filled ballroom was teeming with 200 men in tuxedos — and a smattering of women — whose daily decisions can collectively make or break the global financial markets. Most were picking over a lavish dinner that included rack of lamb and crème brûlée. Others were preparing to sing bawdy show tunes.Kappa Beta Phi, an exclusive Wall Street fraternity whose members include big-name bankers, hedge fund billionaires and private equity titans, met at the St.