Level Overrides for individual reference files.

Can you set ONE reference file only to NOT accept Level Overrides in a master file with multiple references?  I cannot seem to make this happen.

I have a main sheet file - A1.  It contains 3 drawings, floor plan, reflected ceiling plan and an electrical plan.  Each of those references is a text file over the main floor plan file.  

Can I have the floor plan file only NOT accept level overrides while the other 2 are overriden?  Does that make sense?