I am trying to add a promotion discount as a set of item A and item B together grants $0.20 off item A (purchase with purchase).

I have tried different combination of the condition rules like grant promotion point per unit paid, discount only on specific product, but there is a problem where the discount keeps getting applied in each line regardless of quantity. Is there a way for the discount to be applied one to one by quantity? 

Examples of the correct discount application is:

Buy 2x item A and 3x item B -> 2x $0.20 off item A

Buy 4x item A and 3x item B -> 3x $0.20 off item A