OK, so you want to be able to capture the fact that Invoices a, b and c are new and then, somehow, modify the query which selects the detail rows such that it filters them at source to include only those which belong to a, b and c?
I can't think of an elegant way of doing that in SSIS. Easy enough in T-SQL.
To be honest, I am very surprised that these tables do not have date columns which you can use.