With the server costs they have shown i would not recommend trying to take over their deal they most likely host at some game server renting services. Depending on your location you can start up your own server farm and connection with that kind of money. Meaning you own that stuff rather than paying ~5000€ per year to rent it (which is either a astronomically rip off, wrong hardware beeing rented or plain false information).
1000/500mbit in germany is around ~1500€ per year and plentyful to host as many game servers as you can imagine, take the remaining 3500€ to start up your 4 server pvp cluster for the first year. If you go for the renting route DO NOT rent game servers but rather setup your own, be sure to rent a system with SSDs (game servers tend to lag while saving and ark seems to set an example at sucking at this).
That beeing said, managing a cluster is much more expensive in terms of time rather than money. The hidden costs of Ghost Division easily outnumber anything shown to a full order of magnitude. Good luck finding 10+ people sinking their life into this without getting anything in return other than flaming kids and delusional maniacs in your forum telling you how shitty you run your project.