INVESTORS HAVE 5.5 PCT OF DATAREX SYSTEMS <DRX> A small investor group led by Melvyn Gelch, a Providence, R.I., surgeon, told the Securities and Exchange Commission it has acquired 60,840 shares of Datarex Systems Inc, or 5.5 pct of the total outstanding common stock. The Gelch group said it bought the stake for about 935,000 dlrs for investment purposes only.