Need an option to configure the method of discount calculation either "retail favour" or "customer favour"

Now this option is available only in least expensive mix match discount type.

System is always favour customer for the discount calculation.

eg:- In a mix and match promotion of 10%, there are two line group, in which 3 items are included



Suppose

1) Item A having price 100 and in the group A

2) Item B having price 120 and in the group B

3) Item C having price 600 and in the group B

If we add item A and Item B as the promotion pack and system is applying the 10% discount.

and if we add the Item C to the same transaction, system remove the discount from Item B and apply the 10% to Item C, because Item C is having high price than B [customer favour].

So here we want to setup the calculation in such a way that the discount should apply to the item having less price in the line group.