Complex sentence: Act III's next task was to ensure they had a monopoly in the Piedmont Triad: in 1991 it bought WGGT's programming and merged it onto WNRW's schedule.
Split into simpler sentences: Act III's next task was to ensure it had monopoly in the Piedmont Triad. In 1991, it bought WGGT's programming and merged it onto WNRW's schedule.