How do I prevent objects from spawning on other objects

Ok I have a question.

I set some objects to spawn in random positions on the screen, but there is a problem.

Sometimes some of them spawn on top of each other (because they spawn at a random location,and sometimes that random location is on top of another object)

Can I make them spawn in random positions, but prevent them from spawning on top of other objects?

I appreciate your response and help.

Please,post a capx....

I had this problem some time ago, this is how I solved it.