How to set IF rule based on grouped data

[jadepepler]

Good Day,
I wish to return either "R" or "NR" in a given column.
This needs to be done on a file level (Column "FILE_REF"), so the function needs to be performed per file.
If column "READY1" contains ONLY "R" values for a specific FILE_REF, then it must return "R" to ALL rows containing that file ref.
If column "READY1" contains just ONE "NR" value for a specific FILE_REF, then it must return "NR" to all rows containing that file ref.

VBA tools/Macros welcome.

Thank you