I'd suggest a small change that would generally help NBEMS usage even though I am not involved in any.
FLAMP is a broadcast mode system that relies on repeats to fill missing blocks. Last time I used it, block resends could be requested, but only with operator intervention. I suggest that a semi-automatic function be added so that (multiple) receiving stations can only re-request what they need and the transmitting station have a method to gather multiple requests (a timeout) for the next TX run.
Changing modem speed "requests" with RsID would also help. FLAMP
already has a multimodem option that could be expanded for this.
RX snr could be used.
Some more specific setup documentation would also be needed. PSM/persist/slot and limiting RsID mode change would make channel utilisation better.
In the end a 2 station link would be able to do transfers at the
channel optimum. Star or haphazard networks would have less
network overhead. If the RX station is not setup to TX then
multiple block transmissions would still work. An RX with a very
noisy environment could "request" a rebroadcast at a very low rate
Cheers Bob VK2YQA