Adding bank account to supplier when exists in AR

Summary

Record with combination value already exists error

Content

Hello:

We are trying to add a Supplier's bank account for Payables ACH, and the Supplier is also a Customer in AR with the same bank account.  Can someone advise how to set this up?    When we use the "+" to add the account and search for the bank account name from the AR account, it does not find the account.

 Also, it is an ongoing question whether the banking information can be setup using the profile tab rather then the primary site tab?

Tks!