The reason I ask is because it is not I who is doing the import, but end users. So, they won't have access to the import wizard... or will they? No, I think they would have to know exactly which table the data was being imported into.
There are many options, but you will have to provide some details on your business process. How is the database deployed? How are the spreadsheets used? Type and frequency of import, etc. Maybe you can simply train the users how to use the native import capability, or you might have to automate some processes for them.