Building Spawning

So, I got a trigger to spawn XXX amount of units/buildings in a region. The buildings are 2x2 tiles, the size of a farm. The problem is, they all spawn clustered up like they were only a 1 tiled building or a footmen. How can I make them spawn in a way so they don't cluster up?

u need to trigger in a loop so each time it checks and finds a place for it, rather then just regular spawning.

In other words, spawn 1 building at a time.