Your question is very open ended. You're starting with the business structure instead of a money making idea.
The part that concerns me is that you want to issue dividends to all the shareholders for businesses that they 'do' together.
Doing usually entails working for wages/salaries. Dividends are the returns for putting capital at risk.
Arrange a call if you'd like to talk and sort out your ideas a little more clearly, I can help give you some direction.
If you want commitment then set up a proper Limited liability venture. This is just as much about making the business work as it is about structuring for tax reasons
I agree with David here. Though I can see that you have a vision for the structuring of your company, you may want to take a step back and revisit the overall planning.
Nonetheless, you can structure a holdings company that can be a "parent" company for all your ventures. This way, it gets more organized. I did it for my company structure and it has been quite beneficial when it comes to organizing my portfolio.
Just remember that even though there is nobody holding you back in creating a holdings company structure, you have to understand that each company, subsidiary, etc., will have the same amount of legal and accounting costs needed to make these legal structures function.