heh...if it really gets on your nerves, go ahead and cut down a few ghosts in the level editor.
Just so you don't make it more annoying for yourself than it already is, here are some tips:
1) only release one batch of ghost at a time (duh!

), and try to kill at least 4 of them before releasing the next batch. It's always preferable to get all 5 killed even if it takes some patience and dodging.
2) avoid touching the star button as much as possible (unless you have nowhere good to move to), so you don't miss opportunities to kill ghosts.
3) once you're done with a batch, get rid of the associated ice block. Having more than one ice block around tends to get in your way rather than being helpful.
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How to kill ghosts:
The dashes is the island and the * are the conveyor belts. Get your ice box into either the X or the O, and wait for a ghost to come out. As soon as the ghost has stepped onto the first tile of conveyor belt it can reach (here it would be the top *), push your box up into the conveyor belts (not left or right!).
If you do this right, you should have no more than 1 to 2 ghosts out in the central island. Of course, once in a while you'd have bad luck and too many ghosts escape. Either be prepare to play dodge or just start over and hope for better luck.