FOF's and more FOF's

I have a problem. I want to make an FOF, in this case, for a ceiling of a building. Inside that building, I want another FOF to flip the gravity. Is this possible? It seems that if I draw a smaller sector, the tag would have to e changed in order to give the small sector a new effect. When the tag is changed, it rips a chunk out of the ceiling. I mean, I COULD make an entire new FOF to fill in that chunk from the same control sector as the flipgravity one, but it seems like there must be a more efficient way. Is there any way to give a sector 2 tags, or any other way to get around this?

Let's assume you have one big FOF (A), and a smaller FOF (B) inside the big one. If you give FOF A tag 1 and FOF B tag 2, there will be a hole in FOF A. To prevent this, give a second linedef on the control sector for FOF A the FOF effect and a tag of 2. This way, FOF A will fill up all sectors with tag 1 and all sector with tag 2, and FOF B will fill up those with tag 2.

Okay, that makes sense, Can't believe I didn't think of that before.