downers all together, sub hits all together, etc. for instance I have 'braaams' from just about every trailer instrument library in one place.
You can also create custom folders of just the NKI instruments from various libraries into one place, and they all find their samples no problems (I went a bit nuts with my trailer folder. The benefit of being able to organize libraries as you like is huge, and like Jaap said, I never use the 'Libraries' tab any more as its too cumbersome to scroll through once you get used to organizing the quickload as you like.
This is the best method IMO and what I typically recommend users who ask.