i want to know if you can make your own server

No, not really. I have some thoughts of renting servers but that's a bit too much work to be worth it so will probably never be a thing. What kind of server would you want though? I may be able to help you with it. For example, on server 0 you can use !restart command to play pretty much any game mode citymania has. And it's generally not a problem for me to start another server when I'm around.