Rockaway, N.J.-based Party City Holdings Inc. has entered into a definitive merger agreement with Dedham, Mass.-based iParty Corp. The transaction, which is expected to close during the second quarter of 2013, is subject to customary closing conditions, including approval by iParty’s shareholders. iParty Corp.’s portfolio includes 54 iParty retail stores in New England and Florida, as well as its website www.iparty.com. Currently, Party City operates more than 750 company-owned and franchise locations throughout the United States, Canada and Puerto Rico.