INVESTOR GROUP DUMPS SILICON <SLCN.O> STAKE A group of Boston investors and investment partnerships told the Securities and Exchange Commission it sold its entire stake in Silicon Systems Inc of 410,000 shares, or 6.0 pct of the total outstanding. The group, which includes HLM Associates, HLM Associates II and their three general partners, said it sold the stock between April 22 and June 9 at 9.00 to 9.125 dlrs a share as the result of an investment decision.