Sounds like the experienced filmmakers think it's okay to not pay the rest. Sounds reasonable.
Thinking about it today, I was thinking that there's also no harm in being discrete about it. As Rik says, people WILL talk [about what they're being paid or not paid, and in comparison to their coworkers]. Still, I see no reason why you yourself can't be discrete about it; you can control how you handle that, at least. And I also see no reason why you can't ask those you pay to be discrete about being paid, or at least, be discrete about what they're being paid. Just a gentleman's agreement. They may still blab, but it might be worth trying? If they blab anyway, oh well.