Ok, so I dont actually know how Loarte and the other winstreak/killstreakers do it, but I do have 2 methods that tend to work. Method 1: Upload a video on youtube and keep going into team tac with the 4 killers till you get domination dome, invite all the dummy ps3s, and then cancel the upload or else the game will end due to poor connection quality to the host. BUT my problem with this method is that people always have crappy connections and end up timing out when we go for a really big streak, so that is where method 2 comes in: access your router settings by typing 192.168.1.1 in your browser, and navigate to a section called applications and gaming. Create a rule that forwards all ports to a dummy ip address other than that of your ps3 but dont enable it yet. Now, get all the killers in a party, upload a youtube vid, and keep clicking on domination till you get dome. Then invite all the dummies, enable the port forward rule, and cancel the youtube upload. The only problem with this is that absolutely no one can join after the port forwarding rule has been enabled, even if they are invited, so I still need to refine exactly what ports need to be blocked to keep people from joining randomly, but that allow them to join from invites. Also try disabling UPnP on your router as this works for some people. Hope this helps and if I ever figure out the real way I will post.
---------- Post added at 11:26 AM ---------- Previous post was at 10:44 AM ----------
I also forgot to mention that some people's connections actually lock a lobby without them even meaning to. In fact, that used to be the case with me and is what prompted me to buy the router I currently use. Little did I know back then that a locked lobby could be a good thing. I actually still use the modem I used to be plugged into when my lobbies would be locked, but for some reason I cant figure out the old settings I used to have.