FOFs

Uuuhm, yeah i have some trouble with FOFs...
I can make them and stuff, but i can't do a FOF over a FOF.
When i try, it makes a hole in the FOF as big as the FOF above it.
Is it actually possible to do? If so, please tell me how.

Absolutlly!
Do the following:
1-Create the first FOF. Let's suppose it has a tag of 1.
2-Create another FOF, the second, like if you wanted to make another sector having that FOF, but instead of tag 2, put tag 1.
I'm sorry if I missed anything, is that I just wrote this in a hurry.

double tagging would be considered a Floor, over floor, over floor
(or, something i just made up: FOFOF - lol)

tagging a sector, to 1 linedef would just be a normal FOF

Okay, thanks!
Now i can finally continue my secret wad... I mean research!