There's an easy way to get this Trophy.
The description is not entirely correct. You can do most of the work in private matches. The whole thing works like this:
Start a private match of Adam Grab by yourself. Pick one of the DLC maps and win it as fast as possible (pick up the Little Sister and let the timer run to 3:00 minutes). Do this for all but one DLC map. For the last one you have to get a few friends or a boosting session (need 4 people to start a public Adam Grab). Start the last map you need in public and win it like the others.
Trophy unlocked!
The DLC maps are:
- Dionysus Park
- Fighting McDonagh's
- Fontaine Fisheries
- Pauper's Drop
- Siren Alley
- Smuggler's Hideout