Welcome to the whipsaw, a common tactic US legacy airlines used for over 20 years to keep their regional partners cheap. It was literally this tactic that had regional pilots living on government assistance because they were paid so little.
The good news is, the whipsaw works both ways. If one of Qantas' subsidiaries can land a better contract, the others will rise too. But if one takes a concessionary contract, the rest come down. Good luck to all involved, you deserve a win.