well, you don't open a gui or anything, you just have to "scroll" so get the right one
That's exactly what you already do :|
How would you implement an independant scrolling control when one already exists to scroll through items? You would have to have a complicated system for switching between the two scrolling controls and it would likely be much worse than just having all the items in one larger scroll list. There really is no good way to have one item slot act as multiple items.