Brief description: I am mid import and have given up on creating a full accounts history but I still want to import my legacy sales invoices in a way that they show on the 'action_view_partner_invoices' button when you open a contact - I think the 'res.partner.form'?-. Since I do not want to deal with legacy accounts, I don't want these to contribute in anyway to the journal or ledger. 

The only potential way I can think of doing this this is to combine the view shown by 'account.action_move_out_invoice_type' with a new custom model - something like account.move.legacy - which has the same fields but is not attached to the actual journals ect so when a partner is opened all invoices history is shown for them.

I know nothing about Odoo development so I unsure if this is even possible, if it is, how complicated would this be for me to do?