Please Help with Trigger Problem

[Progesterone]

Dear all,
I have a computer player's base set up, with units placed to defend certain chokepoints. The trigger I am using, creates x number of computer units in an area, then sends this unit to attack the "human player base".
However the problem I face is this: because there are already computer units crowding around certain chokepoints, sometimes these created units will not be able to passage through these chokepoints and will just get "stuck", wandering around instead of attacking the human base.
Is there a trigger that solves this problem ?
Thanks a lot !

 

[TomTTT]

I would just suggest to add the ability "Ghost" to those units. If I'm right, it should remove the collision of those units. If I'm wrong, just set those units Collision Size in the Object Editor to very low.