ABAP RAP : How to Identify selected rows of child entity inside Create By Association Method ?

Business Scenario :
While creating Parent entity I am populating data for child entities and displaying it to the user. The user can then select relevant child entity records which they want to be associated with the Parent entity. ( rest child entity records should not be considered inside Create By association method implementation ).

For Example:

Suppose Reference Account Details is a child entity with 3 records. The user selects first 2 records and hits CREATE. Then I need a way to pass this information to CREATE BY ASSOCIATION method implementation so that I can discard the 3rd record which was not selected by the user while creating Parent entity.

But the IMPORTING PARAMETER "entities_cba" for CREATE BY ASSOCIATION method contains all the 3 records and I am unable to find out which records were selected by the user.

Is this possible to achieve via RAP ?

Thanks & Regards

Akshay Verma