DISCLAIMER: I am not the founder of this and this tutorial isn't written by me. However I wanted to share it because people said it works. Shout out to datThood on se7ensins for this method

It does work!
You need 4-5 Players with a Second Controller to make it work perfectly!
Load the Gametype from Copey and Paste
Save it as your own File to load it faster

1 - Be in the menu with Public Match, Specialist, etc...
2 - Activate your second Controller and invite 2 Friends with second Controller to be 6.
3 - Click to "Find Match" and search for Search and Destroy.
3.1 - The Host needs a very Bad Connection/ Upload something that you dont Connect in another Lobby.
4 - If done right you will be in a Lobby with your Friends with countdown time at 59-58-57 seconds, etc...
5 - Quickly, press Y and put the group to 8 player, and everybody needs to load the Custom Gamemode.
6 - If it says need more Player to start the Game --> your 2 friends back out, and they need to disable their Second Controllers and rejoin You (Host)
7 - Now everybody needs to load the Gametype again.
8 - Then You (Host) has to leave and disable the second Controller.
9 - Join your Friends Session now you should be 3 without any Second Controllers.
10 - The Rest of your Friends can join.
11 - Everyone load the Gametype again and it should start.
12 - In game you need to press Start and see if you have the Ping Bar. The one who doesnt have it is Host and he needs to stay in the Lobby.
13 - Now one Person leaves the Game and activates his second Controller and rejoins.
14 - Repeat Part 13 with a different Person.
15 - Profit?