SAP allows creating multiple Payment Methods for a remittance location, and Ariba OOTB program also imports, the multiple Payment Methods for a remittance location, which will allow us to link multiple bank information for a supplier remittance location.
however In Invoices Ariba P2P ( Paper Invoices) nor Ariba Network ( Supplier created Invoices), The supplier/Buyer in P2P can't select which of the two bank will he want his payment to come in.
Ariba allows to select a remittance location, on the Invoice, and randomly picks any of the 2 Bank ( Payment Method) during posting Ok2Pay/reconciled Invoices back to SAP.
how does other customer currently handle this, don't they have multiple banks linked to one remittance location, and if they do how do they make sure payment is sent to the correct bank, usually when it is paper invoices, Supplier mentions the remittance Information to which he wants to be remitted on the invoice and the payment is processed to one mentioned
We are currently working on the same scenario and SAP has confirmed that we could only used 1 bank details in Ariba.
In your case you might have configured 2 of them but Ariba will only pick one as you mentioned I guess in your case I might be taking on the basis of Alphabetical order.