Message mapping help on "If then else"

Hi,

I am struck in a mapping logic,

If QUALF equals "013", then map the same context of IDTNR to target.

If QUALF not equals "013" and QUALF equals "001" then map the corresponding IDTNR value of  001.

001 -- Should fail

013 -- Should pass

<---Context change--->

001 -- Should pass for 001

Ideally the expected values are Should pass (013) and Should pass for 001 (001) with a context change.

The Should fail value occurs because the first context QUALF has the values 001 and 013 in the same set of records.

Need you inputs in getting the desired result without a UDF.