System does not set field BVORG of BKPF table (Cross-Company Code Document Number) in FI documents, although there are multiple company codes involved in the posting.
Cross company processes in HR are never posted as cross company process in FI. Every FI document for each company code involved is posted separately in FI and not as one cross company process. Therefore BVORG is not set in those documents.
For posting process in/from module HR, cross-company code postings are possible. So that one would expect that in the case of cross-company code postings from module HR, field BKPF-BVORG in the corresponding created FI documents is populated accordingly, just as this is done for all other postings. But this is not the case for cross-company code postings from module HR as HR calls accounting and transfers its data to accounting separately for each involved company code. Accounting only receives one single accounting document for one single company code so that accounting cannot recognize a cross-company code posting, and accordingly in accounting no cross-company code processing can be done.
This is the corresponding standard system behavior/design for postings from module HR.
In order to set FI documents relation, customers can use field BKTXT of table BKPF as a kind of link between the FI documents, considering that BKPF-BKTXT contains the run-ID (run number) of the HR payroll posting.