Connect Slots Across Multiple Servers

I'm attempting to link multiple servers to my Minecraft hub server. While I have a good idea of how I can link the servers with portals in the hub, I'm confused as to how I can have the slots of the hub server show all of the users online all of my servers.

Example:
sVanilla server has 20 users online: 20/28
Factions server has 25 users online: 25/30

I want the hub server to display the total online out of the two servers (45/58). There are a number of hub servers that have done this. Any ideas?

Any ideas?

EDIT by Moderator: merged posts, please use the edit button instead of double posting.

 

I know that in the bungee cord config you can set the "max players" it isn't really the max players its just a number that displays there. You could do that.

 

You can set the max players to the total number of max players across all servers, then create fake Players that fill up the player count.