Android hotspot usage

So recently (on my 1+1) I opened my hotspot to some of my friends to play a game which has never caused problems before. This time however, all of the data was used so I was wondering if there was a way I could tell who used the most. By default, in my settings, it only divides my data usage by the processes across however many days it has been. Rather than breaking it down into different users.

Nope, the default android hotspot metering doesn't record by client, it acts as an access point and a DHCP server, nothing more.

Is there an app that allows me to monitor individual users?

It would have to be an app that served as a hotspot replacement. I'm not aware of any app that does this.