I think it is time to do what should have been done in the past, Stand together as one, draft a new contract with set wages and conditions, call a meeting with management and say this is it, take it or leave it, stop work as a group until they agree.
They wouldn't know what hit them nor do they think you would do it.
Management would be on the back foot and would have to agree within a couple of days.
From then on you have the power and unfortunately that is the only thing these guys understand.
Australians, Brazilians and Local guys must do this as a group, ground the aircraft.
They are not ready for HKE to disappear yet so get on with it guys, now is the time to act.