This achievement is fairly easy to get, just make sure your team stays together throughout the game.
Starting RoomThe bots will randomly spawn from different directions. Just make sure to stick together as there shouldn't be much problem getting through this section.
Alley/DocksThere will be bots in this section and they should be easy to beat. As you get close to the over pass, there will be a sniper. An easy way to kill the sniper is use Genji's deflect to kill her instantly. Continue playing and sticking together and you should be able to make it inside the house.
House/AlleyAs you finish the docks, you will enter a house which leads to another alley. The hardest part of this section is the major boss. This boss has a lot of health and can deal a lot of damage. An easy way to deal with this boss is to lure him backwards towards the house and keep moving back and chip away at his health. You will eventually kill him and move on to the next section.
Circle RoomKeep staying together as you will fight more bots and a the ninja. If someone gets attacked by the ninja, make sure to help them out or you will need to start reviving each other.
Final RoomThis is probably the hardest part of the mission. The best way to beat this is to stay in a death ball so Moria has an easy time to heal everyone and you can help support each other. Kill the major bosses, and once they're gone, head to the top and wait for the drop ship. Make sure you dont wait at the bottom since you can easily get pinched and the team can fail.
Good luck to everyone attempting the achievements. I will update my solution as soon as I play some more and find better strategies for different sections of the game.
Below is the video of my group getting this achievement.
Note: Beating the mode on Expert automatically gets you the Hard achievement.
My team for this run included the following players:
Moira -
TekmoteReaper -
USG AESOP SLMcCree -
good Super manGenji -
Xenic Acid