Same bank accounts for 2 suppliers in R12 instance

Hi,

I have come across an user requirement where in i have to create a parent supplier with say a name ABC Pty Ltd and it has a bank account (123456). Also this parent company has another company DEF Pty Ltd but are using the same bank account number (123456). But when i am trying to use the add button in the Bank Details section in supplier creation, i am not able to select anything when choosing Account Name, Account Number or Bank.

When i click on the create button and try creating a new account it says this account is already in use for the Operating Unit i am in.