^
(I meant to type 100 ms there.)
To clarify, I am NOT talking about those virtual choir / orchestra videos you see all the time. Those are all separately recorded to a click track, and edited together later.
I am talking about true real-time musical collaboration with large groups. To my knowledge, this is not currently possible unless you have a fiber-connected private WAN.
^ Boosting this to hopefully get some ideas. I know there are people here who are experts in large-scale networking.