DREXEL OFFICIAL HAS STAKE IN EPSILON DATA <EPSI> A senior official of Drexel Burnham Lambert Inc and his father told the Securities and Exchange Commission they have acquired 258,591 shares of Epsilon Data Management Inc, or 9.4 pct of the total outstanding. Kenneth Thomas, senior vice president-investments at Drexel's Los Angeles office, and his father, retired university professor C.A. Thomas, said they bought the stake for 2.1 mln dlrs primarily for investment purposes. They said they may buy more stock or sell some or all of their stake, depending on market conditions, but have no plans to seek control of the company.