Complex sentence: NYU, Harvard, and Columbia have been hosting the recent PKU and Tsinghua delegations, which the delegation also visited corporations including JP Morgan, BCG, and King & Wood, and institutions like the United Nations and the China Institute.
Split into simpler sentences: NYU, Harvard, and Columbia have been instrumental in hosting the recent PKU and Tsinghua delegations. Together we have visited corporations including JP Morgan, BCG, and King & Wood, as well as major institutions like the Untied Nations and the China Institute.