BAPI/Exit on SAVE in SAP Credit Management inside transaction BP

Hi,

I am working on enhancement to update "Collection group" in collection management as shown in below screenshot:

My trigger point is change of "Credit Group" in Credit Management-Credit Profile(below screenshot). Based on what user has selected Credit Group, I need to read this value and read "Collection Group" entered by user in backend, check value in Z table and read "Collection Group", using some FM/BAPI update the collection group inside Collection Management in above screen.

Problem here is, once user select credit group and clicks on SAVE, somewhere I need BADI/Exit to read what value user has selected in Credit group dropdown and based on that I can write further logic to update collection group.

Need help in finding the right place, where I can get Credit group value entered by user at runtime.

Thanks & Regards,

Mayuresh