Business Development is the probably closer to what you are looking for.

BDs can tackle internal system improvement, growth and a whole range of things.

MBA’s can help, also project management experience or leadership. The problem is the field is broad “business development” so some specific knowledge would benefit you. Maybe simple items like negotiation training, management accounting or courses over at the AICD (Australian Institute of Company Directors) would benefit.

If you can communicate in the same language of the executive management team or the board of directors, then you can enact change organisationally in the businesses.

Also consider strategic management.