You can restrict Jobs from working in certain regions by editing restrictedAreas.yml. You can additionally set a multiplier to reduce the amount of money received in a certain area. This is useful to setup if you want to prevent farming in MobArena or other types of mini-games.

restrictedareas:
  area1:
    world: 'world'
    multiplier: 0.0
    point1:
      x: 125
      y: 0
      z: 125
    point2:
      x: 150
      y: 100
      z: 150
  area2:
    world: 'world_nether'
    multiplier: 0.0
    point1:
      x: -100
      y: 0
      z: -100
    point2:
      x: -150
      y: 100
      z: -150