On what basis system will pick the account names of shared bank accounts while upload them via FBDI?

Summary: System is providing only one Bank Account Name to all shared bank accounts even if we provide the different bank account names on every record. This is quite understandable and intended behavior of the system. But on what basis system will pick the account name??

Content (please ensure you mask any confidential information): For example, in FBDI template if we provide three different account names of same Bank account record for three different suppliers, then while loading those records in the system, it's picking one name out of those three. But please explain on which basis system is picking the Account Name?