I am not sure it is possible on the GTX.
Breaking it in two is pretty easy and only thing required to put the two pieces back together is Permatex Ultra Copper RTV.
I have always removed the pipe from my RXDI in one piece. The opening on the GTXDI is a little smaller than the RXDI. I was actually just observing this the other day, I think the GTXDI pipe needs to be split.
I put it in in one piece. I removed both brackets and tightened the clamp enough to hold it together but still swivel. Tightened pipe to manifold bolts / nut then installed mag bracket. Installed cylinder bracket and aligned. Then finished tightening the clamp.