So those tripleS new members really can be from R U Next

They can also be some ex gp999 trainees

I vaguely remember seeing something about how the contestants have that S designation signifying the order they joined (Seoyeon S1, HyerinS2 etc etc) and that there are several small S waiting to be promoted to Big S or something like that

Several Girls have in Blogs talked about being Small S and the moment they were told they were being promoted to the Main group, so it would seem the future members are already waiting before RUNext even begun, but it was a long time ago I saw that so I guess it all could have changed since then

But I suspect there is little to no chance of this happening