Skipping few lines from DSO in Char relationship

Hi All,

I have standard DSO in CR which is used to check the lines which are uploading the lines are valid or not.

Below is the structure of DSO.

field 1 field 2 field 3

123 XYZ A

456 DEF A

456 PQR B

While uploading the data, now i want to check the validation of lines which fall under field 3 => 'A' and want to skip the validation for the data of B from field 3.

Is there any standard procedure for removing the validation of lines for filed 3 which is 'B' other than writing the exit.

Thanks in advance.