Row security for mixed alphanumeric MCU values

Hi Everyone.

I have a situation where MCU values are purely numeric, purely text and a mix, with numerics in the middle (BR034X for example).  The data base is Windows based.  I've have a really hard time trying to define row security that works.  My most recent attempt was as follows with Inclusive row security.  Here I'm trying to hide MCU values BUR, ELK, EMP and GIS but it does not appear to work.  So far I can't come up with any range that actually works.  In one setup I tried to enter something like ELK - ELK0ZZZZZZZZ and received an error