In my opinion, you should look into some of the services of a product suite provider for professional online gambling management. I found an article quite relevant for you: www.mangalorean.com/how-much-does-it-cost-to-start-an-online-casino/
We have the same question as you. We are currently building a tool to manage different affiliate accounts on the same platform. There is a lot of work to do and we are doing our best to optimize this tool.