yup. they were always planning to release another GG after RV. SM started something called SM rookies girls and it was full of the trainees that were potentially going to be in the next gg. They promoted some of them on mickey mouse club in 2015 along with sm rookie boys (a couple of NCT members were on there before SM debuted them). Here is yeri performing with them a while after rv debuted
yeri was originally in this group.