How to stop Scroll of Town Portal

Ok, basically, I want scroll of town portal to be unable to be cast while a certain boolean is true.

With most abilities, I can just tell the unit to stop. However, with this ability, this method doesn't seem to work.

What is the easiest way to halt this action?

pause the unit for .01 sec maby? or make a fake town portal

Just tried the pause thing.... No luck...

Order them to move to their position?

I think the UMSWE addon for NewGen has a bunch of events/actions related to Scroll of Town Portal. It was either that or WEU.

if its from an item maby you can detect it using an item and stop if before it uses it,,,