It's not something that is possible at this time. I have made a suggestion for something similar as it would make it easier for me to file taxes, but I don't know that it's very far up the priority list. The best workaround that I might be able to suggest for you is to make a "Non-Taxable" Category and track those items that way. You can then look at your category sales at the end of the month to find your total. Hope this helps!
