Would an n-way conference over ham radio offer good enough latency (if all participants are within a couple km and the signal among everyone is good enough) to make band practice possible ?
Edit: And another problem that's probably even more important for this use case, most common ham radio equipment is simplex (only one person can transmit at a time). In the VHF/UHF range you might be able to engineer a high bandwidth duplex (or TDM) system, but then your range would be limited to a few miles.