VIACOM <VIA>, NAT'L AMUSEMENTS SEEK FAST MERGER The chiefs of Viacom International Inc and <National Amusements Inc> said they met and agreed to work together to complete the previously announced merger of the two companies "as expeditiously as possible." A spokeswoman for Viacom declined to say if the executives had set a timetable for closing the deal. Viacom last week agreed to be acquired by National Amusements for a combination of cash and stock with an estimated value of 53 dlrs a share, or a total of about 3.4 billion dlrs.