trying Codestriker I've found that all comments, submitted against some file and line are grouped together, so it is impossible to mark some comments as Invalid and leave others Submitted. From my point of view, this is usefull feature. Is there any possibility to not group such comments?
I'm afraid at this stage it is not possible. Issues are linked to file:line, which in hindsight is unfortunate. You can add a feature request so it is added to Codestriker's feature request database. I thought this had been asked for before, but perhaps it was just on the mailing list.