Possible to restrict specific units from TP effect?

I wish to deny a specific unit passage with Town Portal scrolls. What's the easiest way of going about this? Is there some classification evolved that may solve this, or must I trigger it? If so, what would you suggest?

Thanks.

Try changing the "targets allowed" field on mass teleport to something like non-ancient or non-suicidal and then give that classification to all units you don't want affected. If that does not work, then that means the mass teleport spell is hardcoded to affect all player's units; you would then either need to trigger the spell effect completely or give the unaffected units to an allied computer player with shared unit control.

That was my first thought, but the ability tied to the TP scroll has targets allowed: Structure, Vulerable, Invulnerable. Thus it seems that field is about the receiving unit (town hall?), not the transported ones.