In order to help negotiate its pending merger with Kawasaki Steel Corp., NKK Corp., has called upon Goldman Sachs Group Inc., while Kawasaki has reportedly hired Morgan Stanley Dean Witter to help with negotiations regarding the possible business transaction. Earlier this year, the same two advisers were hired by Mitsui Chemicals Inc. and Sumitomo Chemical Co. to help negotiate the union of those two businesses, which will form the world's fifth-biggest chemical company. A value for the steel and chemical mergers will be determined when the parties hammer out a ratio for their share swaps, likely to be later this year, the paper said. The transactions are likely to be two of the biggest deals this year. Together they are reportedly valued at as much as $30 billion including debt.