Bigger airplanes (B787, A747, A330...) are using 2 jetways when parked at the gate for a faster de-/boarding process, the A380 even uses up to 3 jetways at some airports.
It would be nice to have the option to add multiple jetways per parkingspot in the Sim as well. At some airports within the Sim there is currently actual a second jetways, but as static object.
Same goes for multiple stairs at ramps, there are often 2 stairs for each aircraft (one in the front and one in th rear)