which API to use for creating Supplier Bank account assignment at site level?

Hello,

we want to end date existing bank accounts on all suppliers at site level and create a new dummy bank account assignment for all of them.

should we be using the below ?

 iby_ext_bankacct_pub.update_ext_bank_acct ( to end date existing account on all suppliers )

iby_ext_bankacct_pub.create_ext_bank

iby_ext_bankacct_pub.create_ext_branch

iby_ext_bankacct_pub.create_ext_bank_acct ( to create new dummy account on all suppliers )

should this be done for each supplier ?

how to avoid ' Bank account already exists error' after its assigned to the first supplier?