Odoo community version (POS)

Hi,

Is there a way to set the POS for a set meal, say selection from category A food + drinks.  But the price for the drinks is less than the original price.

For example, set meal A 

Choice of food from category A (Fish, beef, or pork) = $10 

Choice of drinks (coke, coffee, apple juice) = $5

If we choose set meal, the price for the drinks is only $2

The bill will be $10 + $2 = $12 instead of $15

How to set the set meal?

Thanks!