September 6 (SeeNews) - The Zagreb Stock Exchange (ZSE) said on Tuesday it will add Djuro Djakovic Holding [ZSE:DDJH-R-A], hotel operator Istraturist Umag [ZSE:ISTT-R-A], port operator Luka Rijeka [ZSE:LKRI-R-A] and hotel operator Riviera Adria [ZSE:RIVP-R-A] to its 25-share benchmark CROBEX index after the end of trading on September 16.