The OP will end up doing whatever he likes in the end.
Why bother to show up and ask advice, if when everyone tells you their opinion based on fact, on things they've seen, on things they were told by others who experianced them... you'll just go "Pfft, you're just fear-mongering!"
I asked about it already, how are you going to move a 12 ft hungry snake to feed it.. then manage to get that 12 ft snake in feeding mode back into the cage with the OTHER feeding mode snake in it, when you aren't even suposed to handle them right after feeding? Why would you want to?
People here (as stated before) are not here to diss you or naysay your idea just because we want to make life difficult. Most everyone on the site are offering you advice because WE CARE ABOUT THE REPTILES. If you aren't thinking of the snake's needs and safety first, then you've missed the point of owning a pet.
You said you'd probably house them seperately, and that's great IF you do it. If you choose to ignore all the advice and house them together and something goes wrong, you won't get a whole lot of sympathy from the herp world. At BEST you'll have a possibly injured snake.. at WORST you will be injured and then we get another headline about how "dangerous" pythons are.