Try Advanced Library, with this tool you are even able to put all files for one item in one folder, means character, pose, cam, light whatever you want. Well, you cant access the non character items in this case from poser but why should you when you use Advanced Library. Now you have e.g. one cloth with all the MAT poses together. Great!!

You can, but you don't have to do that in order to have Advanced Library display the different categories together...

And even if you move all items from the different library folders into one folder, you should still be able to use that setup with poser, using shortcuts. (But that's relying on Poser supporting that in future releases...)