Why have the Group Base open up to do comms for every job???
Make sure there is someone at your station to do comms. If that means running with four members on the truck, instead of the five that turned up, then so be it.
I really dont see the need to get Adelaide fire, Group Base, Region HQ, or whoever, to do comms when the stations are perfectly cappable of having comms run from there. Thats why we have the occurence books people.
BTW, I am in a brigade that regularly runs with four people on a truck so that someone can stay back and do comms. And the person who useually stays back is me, and thats by choice.