Normally, I would design these kinds of tubes in part using intersecting curves and sweep. Import to assembly and get properly attached tubepaths. That places the intersecting tubes correctly for cutting the tube ends in the end.
For this a-form, the main tube ends must be parallel to eachother, thus intersecting curves won't work. Designing the whole frame in Xpressroute results in bad intersections and improper cuts for the middle tubes.