I don't think it's that hard to make it. You just make a lot of check waypoints. And in the checkwaypoints, you check your supplies.
And when your character is ready, you send a message like navsay('ready1') which would be for the first check waypoint.
Second waypoint, after you checked all, you say navsay('ready2')
And when both chars are ready, you can go.
You can browse through navigation messages like normal talking. Its like a casino bot.
You say "high" or "low" and respond to it.
Same thing here, but with navigation messages.
Example:
Player 1 (EK) is hunting
Player 2 (ED) is hunting
Player 1 (EK) reach check waypoint
Player 1 (EK) checks supplies, etc....
Player 1 (EK) sends nav message ("ready1")
Player 1 (EK) waits for messsage "ready1" from Player 2 (ED)
...
Player 2 (ED) reach check waypoint
Player 2 (ED) check supplies, etc..
Player 2 (ED) sends nav message ("ready1")
...
Both players are ready.
Now continue to next waypoint.
If not ready, go refill.
If one has low supplies, he can send navsay("refill1") or something like that instead.
Just have a script running, checking every 200 milliseconds or something, for new navmessages all the time.