Complex sentence: The biggest international result was recorded in 1984/1985 season when team, led by manager Ivica Osim, reached semi-finals of the UEFA Cup, having finished the domestic championship in third place, where they faced Hungarian team Videoton.
Split into simpler sentences: The biggest international result was recorded in 1984/1985 season when team qualified for UEFA Cup having finished the domestic championship in third place. FK Željezničar, with Ivica Osim as a coach, reached semi-finals of the UEFA Cup where they faced Hungarian team Videoton.