$PRP

I have a question about $PRP commands. I use a $PRP:"SW-File Name" string to display the part file name in a drawing stock list. The particular result I achieve is a 13 digit string, something like this-

41044-011-004. The 004 part of this string is actually the detail number of the part. My question is; how can I write a $PRP command that masks the first 10 digits of the part number, displaying only the string 004, in another part of the drawing stocklist. I appreciate any suggestions.