The military lads and lassies have a freq for practice pans (245.10) perhaps the civil folk should have one as well to reduce the traffic on 121.50.
There are other emergency freqs set aside for scene of search etc, perhaps one of these could be used. If a full emergency is taking place on 243.0 they tell the traffic on 245.10 to "go away please" and they could do that on both freqs if required