OK This was OBVIOUS it would happen.
I believe once NIcole leaves PCD, that will be end of the group, the other girls realized that, saw the end really near, and they now notice they lost her time supporting Nicole, as they are just nobodies and won't have a musical career. I think they were just commfortable at the beginning, as they didnt have to bother about singing, and now Nicole is going solo, they see they have no future musical career.
What NIcole is doing is totally unfair to the other girls, true. She shouldn't use the PCD group, name, songs and concerts to promote herself...but they did this because there's no difference to what PCD has been since the very beginning: just Nicole.
The other PCD girls blaming Nicole for stomping on their dreams in unfair too. Why didn't they fight since the very beginning for singing lines, and more media attention? One thing is for sure: Nocole sings the songs, and is the center image of the group, and PCD are huge thanx to her. So, as painful as it does sound, their dreams started coming true thanx to Nicole.