I'm a newbie use of Multi Index Containers, apologies if this question is facile. I have read through the Boost online documentation but am still a bit stumped. I have a container that contains shared pointers to instants of a custom object type (in this case, financial market orders). The container has an ordered-non-unique index defined by a member function of the object. Specifically it is the object's state code, an integer. At any point in time, I would expect several objects with a state value of 1, several with 2, etc. I need to pull back the set of objects in a particular state, to a set. I intend to use the set in testing to 'do something' with one random object in that set, but to all intents and purposes I just need to get the shared pointer to an item in State=1. How would I pull back the set (or analogous container) of objects that are in State=1? I am thinking that I first get a reference to the index in question, which is fine. Would I then do a find(), and would that find() operation return a set-like object? Or, would I need to do a lower_bound() and upper_bound() operation to find the two enclosing iterators, and then copy all shared-pointers-to-objects to a std::set, and then operate on the set as normal? Thanks in advance for assistance with this, help is greatly appreciated. Steve [I'm aware that if I change state values, I have to do so via the modify function, via the index, been bitten on that point before.]