No Collision with Unit-Type

I have a group of units moving along a playing field, I need thier Collision Size set to 50 or else they look rediculous. The problem is they need to be able to move over themselves. IE: If one unit moves left at another unit, they need to easily pass over each other without using the trigger to disable collision. Basically, like the title of this thread says, I need a unit to not collide with certain unit types.

Its a bit of a long shot, but I figured it was worth a thread. Ideas?

You can investigate setting them as Workers, since in melee the peasants/peons/etc. don't seem to collide with each other when harvesting.

You can look at the possibility of using Flying movement type, but they probably won't collide with anything, then. Perhaps you can just use Group Separation; not sure how that behaves with non-flying units.

1) Worker Class: No effect.

2) Flying Units: No Collision on everything.

3) Group Separation: Has no effect on non-flying units aparently.

Thanks for the ideas though.