This is a terrible fucking idea. You should return the sojs if you can't get everyone in.
Wasn't this easier originally do to a well defined CIDR block?
30 people you are going to try and get on the same server.
Some of the IPs I got quickly in a few games:
35.230.100.27
35.197.31.125
35.83.155.232
34.82.198.68
35.277.188.10
34.127.15.5
34.145.29.139
34.105.15.80
34.82.135.94
34.145.8.213
35.199.180.176
35.230.29.198
34.82.73.195
34.127.127.164
34.145.101.170
34.127.15.5
35.199.187.41
35.199.172.10
34.105.65.105
These are public endpoints registered to both amazon and google cloud. (dnschecker.org)
There's also no guarantee that your publicly facing IP (the ones in the list above) map to the same server. See:
https://cloud.google.com/load-balancing/docs/tcp(Yes there's this video:
https://www.youtube.com/watch?v=F0roxaZm2AM which at least implies it's 1 public endpoint per server so that's good)
However at the very least verify everyone sees the soj counter tick up when you finally all get on the same endpoint.