That’s pretty cool. Took a quick look at the relationships those languages have, and it seems that Malay is the odd one out, all the others are in the sinitic family. I would expect that if you learn one, your mind isn’t going to explode if you try to learn the other two. However, Malay is completely different, so jumping into that world may require some extra effort.
To give a European example, if you already know Norwegian, learning Swedish it’s only one step away. Jumping into Danish or German at that point can be done, but it will require some extra effort. A similar situation exists between Italian, Spanish and Portuguese.