If there is no way to distinguish which table they came from then you have a couple of choices.
Change the field name in one of the tables so that they don't associate. Then you can create separate tables displaying each tables data. Of course they will not automatically associate if you also need to do other things with the data.
Or you could create a new field in the load with a value of A or B that would then allow you to filter in the app for emails from each table. This would give you both the association as well as the ability to filter the tables.