I don't believe you would be able to see it in your bandwidth utilization. I suppose you would be able to estimate which stream you're receiving based on number

I don't believe you would be able to see it in your bandwidth utilization. I suppose you would be able to estimate which stream you're receiving based on number of callers in a conference but your outgoing stream is always going to be the same, assuming you're not network constrained. The stream is a single H264/SVC stream which contains layers of varying quality. It's sent to the Zoom "cloud" where the appropriately sized layer is extracted and forwarded to clients. It's called selective forwarding and it's essentially how all of the WebRTC style video conferencing solutions work once there are more than 2-3 participants.