Dear all, I have an application where something we call a "categorised container" with colleagues comes very hand. We do currently have a working version and I am looking to see whether it's possible to do some refactoring on that using Multi-Index. Here is an exemplified explanation of what constitutes a decision-making point for me. I would be pleased if anyone here could tell me whether this facility is available under Multi-Index: multi_index_container< T hashed_non_unique<...>, ordered_non_unique<...>> my_container; Now, is there anyway I can get all elements of my_container which have a certain hash and sorted according to the second index? In our own local terminology, we call that retrieving all the elements of a given CATEGORY in a sorted manner. (Sorry I'm not still fluent in the MultiIndex syntax to make that more formal with actual code.) TIA,--Hossein