Auto upgrading multiple single orders to a bundle

[gummies]

We are a one product store. We offer in bundles of 1, 2 and 3. Is it possible so that if a customer adds two single bottles to their cart, they will automatically be upgraded to a 2 bottle bundle? Same if they order 2 single bottles, they will automatically get upgraded to the 3 bottle bundle. 

Can this easily be done using the Buy x Get y automatic discount?