Conveying the message of Islam to people living on an isolated island

Q: I read that there’s an isolated island off the coast of India, the sentinel islands. A tribe of people dwell on this island and have been isolated from the rest of society for centuries. They are unaware of the cultures, religions and technologies that exist throughout the rest of the world. This group of people and their way of life are protected due to the fact that they haven’t been exposed to half the viruses and diseases that exist on the mainlands. How will this group of people be judged?