Complex sentence: Generally, the winners and runners-up of the two divisions are promoted to the 2nd Bundesliga, but the B-teams of clubs in the first two divisions are not allowed to be promoted.
Split into simpler sentences: Generally, the winner and runner-up of the two divisions are promoted to the 2. Fußball-Bundesliga, but the B-teams of clubs in the first two divisions are not allowed to be promoted.