Of course there is, but start paying them the market rate: Start recognizing them for their professional services and treat them as professionals.
Why they're going to Calian.... I just talked about the pandemic and a government that had frontline workers and was refusing to pay pandemic pay to the frontline workers. That's just an example of disrespect. Add to that a Phoenix pay system: I'm sorry, but nurses and doctors and others need to get their pay on time and correctly. If you go to an agency and you do the same job, you get paid better and you get paid on time and properly every time. You get your overtime on the next paycheque. It is more and more attractive.
Plus, I would say that Calian is actively recruiting disgruntled or demoralized workers from our bases to go over, because they then get an additional 30% overhead from the government for doing absolutely nothing.