How to disable other promo discounts for Buy together combinations

Hello! I hope you can help me.

This problem bothers me for a while =)

Is it possible in cs-cart v3 to forbid the application of promo code discount to the “buy together” combinations?

I have a promo code that can be applied to all the products and provides a discount. And I want to add product combinations to some of the products which will have lower share price. But I don't want other discounts to be applied to these combinations as they already do have lower prices. How can I manage this? I've tried to set different conditions in the code promotion but none of them works =(

Please help me to solve this problem, it's very important.