Solution : https://service.sap.com/sap/support/notes/458295 (SAP Service marketplace login required)
Key words : 
contact person relationship reason, existing contact person relationships, source code corrections, attached correction instruction, existing contact person, visible contact person, contact person, existing entries, crm system, business partner
Related Notes : 
       
| 442332 | SAPKU30006: Support Package 6 for EBP 3.0/CRM 3.0 |