When you loop, you loop the whole pattern. So if you change the loop points, they apply to the pattern as a whole.
There aren´t many machines out there that can do what you ask. One of them is Kawai Q80 EX (and EXe) where you can choose the bar at which the phrase ends and loops.
But compared to the power of the XL, the rest of the specs for the Q80 are absolutely poor