This should be the relationship that you have:
Account::Account Number = Payee::Account Number_fk
Your script only changes layouts, it does not modify values in any field so I don't see how that does anything with the PayeeList field.
Am I correct that you want to put a list of Account numbers in PayeeList for a single record in Payee to list all the accounts that should link to that Payee record?
If so, a join table is a better option for you:
Payee::PayeeID = Payee_Account::PayeeID_fk
Account::AccountNumber = Payee_Account::AccountNumber_fk
But I am not sure that I understand what you want to do--so this may or may not be the best option for you.