Was in the shower and had an idea on what could be an interest medic mechanic.
Basically it would be a dart (or whatever) that the medic would shoot into the monster (or wildlife) that would cause an AOE bubble around the monster for a period of time. It would basically be a DOT with a heal on it.
For simplicity sake lets say it does 4 damage per second. If one hunter is inside the bubble he would receive 4 points of healing, two would receive 2 points, three would receive 1.33, and all four would only get 1 point a piece.
Damage to the monster would always stay the same, and only happen if there are hunters in the bubble.
The numbers would have to be fiddled with a bit, but I think it would be an interesting mechanic.