GROUP SELLS STAKE IN COMDATA NETWORK <CDN> A group of investment firms which had once sought control of Comdata Network Inc, told the Securities and Exchange Commission it sold its remaining 1,113,500-share, or 5.9 pct, stake in the company. The group, which had owned as much as 9.5 pct of the total, said it sold the stake on March 27 at 15-3/4 dlrs a share. Last week it sold 455,000 Comdata shares. Group members are CNI Partners, an investment partnership, Mason Best Co, a Texas investment partnership, and Houston Imperial Corp, a real estate development firm.