Custom List to show only the GL #'s that pertain to a certain Customer

Is it possible to create a list( the list will have our gl codes that are for inter-company transactions, those company's are not on Netsuite, these gl codes reference those company's cost centers) that you can attach to the customers record so when this customer goes on the customer center they can choose the proper cost center this item should be charged to?

I tried creating a GL List that would list out the inter-company locations, this list I wanted to expose on the customers record, they would choose none if they are a real customer or they would choose their location if they are part of our company.  Then I wanted this list to reference another list which would have that locations gl codes, but I can't figure out how to tie them together.