Invisible intangible FOF

[Sonic Destiny]

How exactly do you make an Invisible Intangible FOF that surrounds a whole sector?
And when i try to make one linedef be an IIFOF when i play the level i die constantly

 

[Flame]

They are set up as if you were setting up just a standard FOF.
Only you are using the Linedef action of 58 rather than 25 or 59

Make the Floor height of the control sector to match its sector that it tags. Same thing goes for the Ceiling height as well.