Is it possible to make that FF depend on other ? Imagine scenario where we create a feature flag to enable a 'shipping' (lets say it allows user to buy a 'physical' products , in addition to virtual one). Now users from specific countries can have access to 'fast_shipping' Feature Flag that allows to use some 'fast' delivery provider Of course fast_shipping should not be enabled when 'shipping' flag is disabled. Is it possible to make this kind of dependency? or we need to make sure that fast_shipping always has a all rules that 'shipping' does?

It sounds like you're looking for prerequisites: https://docs.growthbook.io/features/prerequisites