What about using a blockchain internally within the country to manage the high throughput and still avoid centralization by relying on a single "trusted" third

What about using a blockchain internally within the country to manage the high throughput and still avoid centralization by relying on a single "trusted" third party? For e.g., mining operations can be distributed within the country itself to ensure decentralization within the country. Then this internal blockchain network interfaces with the slower and more expensive bitcoin blockchain to do final settlements? Could this work?