By advancing slowly so that only a few enemies will appear at a time, you will have better chance of killing them instead of the opposite. This is especially true when confronting enemies armed with range-weapons.
Blunt weapons are the weapons of choice.
Use it accordingly. Ranged-weapons still rules. Try to put a couple of shots upon sighting the enemies before they can closed-in on you. Meanwhile, the rest of the team should be busy shooting at the enemy. After the trading session, remember to move the weak character back down and switch with strong fighter instead.