Its not realy like that, you make the selection for LH and after that they tell you where they need you, LH Pax, LH Cargo, Germanwings or Condor. After a few years you returne to LH Pax, if you want.
CityLine is a different thing.
LH Pilots at Condor will returne to LH in the next year, thats why they start hireing people from outside.