Be able to open an offer for multiple milk options

Could state the milk type you are going for then allow the driver to select an option for others to state whether they want to use a different milk type.
This could be another button with the other milk type option. Each time the button is pressed, the total count is reduced.

Pros:
- Allows more milk types in one offer

Cons:
- May slow down offers with odd numbers of milk types
- E.g.(1) 3 Dairy 1 Oat => 3 Steams
- E.g.(2) 2 Dairy 2 Oat => 2 Steams
- E.g.(3) 1 Dairy 1 Oat => 2 Steams