DS - Group buy tiered discounting

Need the ability to launch group-buy campaigns that apply tiered percentage discounts as the combined quantity of a specific product model increases—even when shoppers choose different size variants. Admins should be able to create, edit, and reorder tiers (e.g., 1–17 units = 0 %, 18–49 units = 10 %, 50+ units = 15 %), and the live tier reached must update for every participant in real time.