It depends on where you place your enemies,how many enemies you place in an area,what kind of script you give them,etc.
The best way to do it is to place your first enemy and adjust the AI script until you get what you want and so on...you will have to do it on an enemy by enemy basis...you can't just give them all the same AI script either.
In addition to the aforemention scripts you might also check out Airslide's AI and David's AI scripts as well.
And you might find various scripts on this forum to help.
And opnening the script and reading it doesn't hurt,either.
It will give you a general idea of what it does and whether it suits your needs or not.