In the customizing of foreign trade declarations in CD, reporting keys for 'Z4' we need to configure the values provided by client - document group & external key.
We want to derive internal key based on this document group and external key. So in order for that we need to link the business transactions to the document group.
As per my understanding we can identify the business transactions by main and sub transactions.
But how to link this business transactions and the document group.
One option we thought of is hard coding the values in the fqevent 1980. So according to main and sub we can decide the document group etc. But is there any other way in customizing itself? So that in future if more keys has to be added, we don't need to update the source code.