@ Sweet_09: Yes. From what I read and know, the 4 hua jai series, each siblings were written by different authors. So, basically, in the 4 hua jai series, there were four authors. One author per each part. As for the Khun Chai series, there were 5 authors. A new author was added to the team. In addition, these authors also wrote The Sixth Sense series too.
I also read that these authors are doing or already wrote(forgot which) another series called "The Cupids". In this series, there are 8 authors, which means three more author joined the 5 authors to write this series,and Ch3 have already brought the copyright to it. Therefore, we should be prepare for another big project coming up whenever they announce it.Maybe next year or 2015. I don't know, just guessing. Lol.