We are a K-8 school, and our middle school students use Chromebooks on a dedicated WLAN. Rate limiting per client is very useful, so that no single student can tie up too much bandwidth, but I'd also like to ensure that as a group they don't use 100% of our allocated bandwidth. To be specific: we have a 50 Mbps Internet connection, and I want to limit the overall middle school (as a group, not merely as individuals) to something less than 50 - perhaps 30 Mbps.
The only way I know how to do this would be at the firewall or switch. If your firewall supports traffic management/rate limiting, you can limit the bandwidth there. Otherwise I think you'll have to do at the switch using rate limiting. Don't know of anyway to do it natively on the ZD.