This achievement can only be realistically gained without hours of attempts by boosting. First off, have the person getting the achievement hide upstairs/in the attic of a useless building. Have the other 3 people that are helping kamikaze the enemies, so that all 3 dies. You must establish an order, as in you, then you, then you. Have the main person stand at the end of the room that is closest to the enemy's town (assuming you are attacking.) Have one person spawn. Have him walk about 10 feet away going in the opposite direction of the enemy town. Once he is in a position that will not make him the main squad spawn, have the next person do the same. Once the last guy has spawned, just repeat the process. This is to get around how the game makes the person in the most dangerous position, aka the person closest to the enemy, the squad spawn at all times. Organizing a game like this, you can always make the person getting the achievement be the closest to the action (barely) allowing him to be the spawn at all times. When me and my friends were doing this, we noticed that suicides didn't count towards the 20 spawns needed to unlock the achievement. Suiciding may work, but I think that the game doesn't count them.