Okay I am still not understanding, so i apologize
What I'd like to do is re-explain it, give more detail and then see what you think.
Each Race is given a number A=1, B=2, C=3 Then Other=99
The number goes into the field called "ETHNICITY"
Then IF they click Other, that goes into the text field called "ETHNICITY_OTHER"
However, unless they check "Other" in Ethnicity, I don't want "Ethnicity_Other" to be enabled.
Hopefully that makes sense and gives you plenty of information.