With the ages of twins differing, sometimes, by only minutes, there is no way the system could put them in the correct order. Alphabetical is about the only way it can show them.
The only way, is as you have done, is to make note of it in the bio. But as Fiona says, please check, as you have Arthur as the second son, when he is the third, and Alfred as the third, when he is the fourth.