I did this sample mission (attached) and I rework the cutter.sqs
Now it's works.
You have not set any condition in the WPs, just drop the way of engineers accross the wires (as you see, you can create multiple wire-blockade levels) and create a trigger to every blockade and call this cutter.sqs.
You can create individual engineer groups, they will work individually. If one group die, the other group can work...
For you I insert a T-72 and I put him WPs with condition. It cause the T-72 stop behind every blockade and wait for the engineers. If engineers destroy the blockade, the tank continue his way.
(My 1.08 ArmA is terrible with bridges, so your mission - and mine too - didn't work in the middle section of Corazol, on the bridge. But I create them in my mission too, and I hope in your 1.11 ArmA, they will work too.)