Cross Validation Rule

I have a business requirement for cross validation rules. We are on 11.5.9. 

In our COA we have a cross validation rule for our segments A -> B -> C-> D. The rule is whenever users will put distribution,  If B Exists then there must be a Value in A, C and D segment. C is a dependent Valueset upon B. That should not be a problem. A & C Valueset has only 1 Value.

Now we are getting some accounting through interface from some third party system. They are using  a particular transaction source. These segments do not have C and D thus they are violating Cross validation rules. So the interface fails for these transactions.