(EDIT) I have already done this and found a super effective way to beat it. I've done it four times in a row so far and beat them all without failing. So we used 5 people and played on the map checkout. This map seems to be an easier map to play and the AI will come at you and there will be lots of cover. From waves 1-4 you are gonna wana be Wild and regular tickers so you can save money. Then your gonna wana have savage drones after that, about 2-3 of them. Just pick off the stranded first using burst fire on the retro lancer. But if you run into a hero, just down him and have someone be a ticker to finish it. You also want to stay in a tight group. That way if your downed you can revive eachother and save time and money. Your gonna wana do this until you have tier 3 unlocked. Then your gonna wana have this set up til the end of the game. Your gonna wana have 1 Kantus, 2 Savage drones, and 2 Savage grenadiers. Have the drones down every thing they see and then when you down someone use the grenadiers to throw grenages on the downed enemy. The kantus is simple. Just constantly heal your team. Also another tip. Whenever you see a silver back, have your whole team consentrate on that. They are easy to kill if you work together. The game will take about 20 minutes, and its very easy once you get used to this strategy. Also you might wana practice the map on normal once before you play, so you can get used to how the AI spawn and when they will rush you. Do this and this will be no problem. Hope it helps. Also if anyone is REALLY strugeling on this I will help. Just send me a message on live. Again hope this helps and good luck everyone!