Is there a mechanism for filing grievances anymore? (Forced reduction in EER scores.)

Out Front Office advised all employees they may only receive one "5" on their EER or else the FO would not allow the EER to be submitted to big-HR. I had three 5's justified by both my rater and reviewer, both of whom are SFS. There are three of us here in this situation.

Is this allowed/legal...I'm not sure what the word is, but this can't be "right"...can it? I'm a member of AFSA, but not sure that will do me any good. Is there a way to file a grievance or is there no leg to stand on?