Airside connection at DFW (LX/AA)

If this questions has been asked before, I cannot find it, so
apologies/thanks in advance if you can simply point me to the right
thread.
We intend to fly GVA-ZRH-DFW-YVR (Geneva-Zurich-Dallas-Vancouver) and
back (symmetrical route).
I have already checked on the DFW website about transfers and it
states that "The Skylink high-speed train, inside security, connects
all five terminals with an average ride time of less than 5 minutes",
but the website does not make it clear whether one needs to cross US
immiegration to make an international transfer.
http://www.dfwairport.com/transport/connect.html
Does "inside security" mean when we step of the LX (Swiss) flight in
DFW that we will not have to clear US immigration to travel through to
Canada with AA?
The reason that I am asking this question is that although all the PAX
have passports valid for the destination (Canada), the newer machine
readable passports are required for the United States and not all the
PAX have these. If it is necessary to pass US immigration to get to
Canada it will simply be easier to choose a route avoiding a transfer
in the US (GVA-ZRH-YUL-YVR for example).
I know that one has (or did have last time I was there) to pass US
immigration at JFK to transfer, but some airports (LHR being a notable
example) operate airside inter-terminal transfers...