Hi Maria,
It sounds to me as some tables in FI module (for instance BSID and BSAD, BSIK and BSAK, where you have open items for vendors/customer and after some processes -payments, for instance- is transferred to the other. Both tables are equals, but open items always have less lines).
For archiving, if you manage a customer table, you can use the archiving object BC_SBOOK (tcode AOBJ) as a template and create your own customer object with your reports (for archiving, deleting,...). In archiving usually you run a process (with tcode SARA) where you create a file and where you made your checks. After, you can delete data using this file.
I hope this helps you
Regards
Eduardo