I have a large old chimney that is the chimney for my house's old cook
fireplace. For efficieny purposes, I would like to do the following: I
want to insert a dual flue stove pipe from the first floor at the top of
the cook fireplace to the roof (two story house with attic). I would
like to install a woodstove in the cook fireplace on the first floor and
use the woodstove on the second floor accessing the second stove pipe
(chimney already has an access hole on the second floor). The reason I
want to run the double pipe all the way down to the first floor even
though the second stove is on the second floor is that I think it will
make cleaning the second pipe easier if I can access it from below. I
would just need a T joint on the second floor for the exhaust from the
second floor stove.

My questions:

1) Is this a feasible setup?
2) If yes, what sort of pipe do you use in a chimney like this?
3) Are there double pipes already joined like this?
4) Will there be any problem with back drafts from the second floor
stove's smoke going up the pipe but then back down the other pipe when
the first floor stove is not in use?
5) Would I need a "damper" (not sure if that is the right term for a
pipe)for each pipe to prevent back drafts when one stove is not in use.
6) Can the stove pipe be "hung" from the top of the chimney with some
sort of mount at the top of the chimney?

Thanks in advance for any information on these questions.

Rob