Originally Posted by
TEAMVALOR786
I would do this by instead of segregating a entire area, I segregate the gate that has the US departure. When it leaves, just take down the immigration and customs area and move it to the next gate that is having a US departure.
Not sure this is more practical. Maybe making Terminal 5B US preclearance might work. But it already has a lounge. Not entirely sure where you'd put the pre-clearance part (maybe underground and make the train one way for arrivals only), but a lot of the US flights fly from there already and can probably move enough from Terminal 3 and 5C to make it work.