Before your next platform renewal, ask your admin three questions:
Where does a buying group exist as an object in this system, separate from a person and an account? Can you score that object, and does the score change when a second or third role joins? Can you report group-level progression to someone outside marketing? If the answer to the first question is no, the other two are already decided.
Bring the buying group into any platform evaluation early.
Some vendors will immediately show you how they model it. Others will start explaining the custom work required. That distinction tells you a great deal. Do not automate what you have not yet understood.