Consolidation is the strategy being adopted by major players such as American Business Information Inc. (ABI), Omaha, NE, to integrate its direct marketing operations. ABI chairman Vin Gupta said that last week's acquisition of Walter Karl Inc., Greenwich, CT, is a sign of things to come. "In brokerage and management, we weren't strong,'' Gupta said. "There are a lot of small players in list brokerage and management. We want to acquire them and turn this into a bigger brokerage and management operation." Gupta stepped down as CEO last year to concentrate on long-term goals. His primary mission is to make ABI, which maintains one of the largest business databases in North America, a billion-dollar company within the next four years.