JSZ
55
You can do that in the arranger. You would have Pattern 1 followed by an infinite loop of Pattern 2, then when you want to you can jump out of it to Pattern 3 which is automatically followed by Pattern 4 looping infinitely. Or if you decide to skip Patterns 3 and 4 you can go straight to Pattern 5 and 6.
OT should be able to handle what you describe no problem. My experience with this kind of unexplainable difficulties was that they appear less and less as you gain experience with the device.