Boutique Derivatives Shop

I have some capital to start a business, and I understand that brokers need certifications to legally sell derivatives. I want to start a small brokerage that only sells derivatives to a specific group of clients, and I am interested only in the legal plumbing behind a specialized shop. What would you expect to pay a broker for this sort of position?

Does anyone here have experience with this? If not, am just looking for resources to read. Maybe brokers here could give insight, otherwise will reach out directly to some of these smaller specialized brokerages. Thank you.