Hi, Boost newbie question regarding indexing of multi_index_containers. First a great big thank you to Joaquín M López Muñoz for sorting this library out. Lovely job. OK I have a question about indexing. Probably one for Joaquin. I have a structure that can be indexed on the following keys: 0: identity -- unique - this is fine. 1: int position; -- non_unique - this is fine. 2: int priority; -- non_unique - this is also fine. 3: vector<MyStringType> -- non_unique - but NOT fine. So number 3 is the problem. Am I right in thinking that the multi_index_container does not handle this case? i.e. where you would want a given SINGLE element to be indexed on a variable (unknown) number of keys, in this case as many strings as are in the vector. Although strictly they are not actually separate keys, there is just one non-unique key, but a given element can have multiple instances for this one key. Of course I can workaround this by having another structure to handle this or alternatively wrap up the element a multiple number of times, as many as required by the length of the vector of strings. But I was wondering if there are any ways of handling this in the basic library. Apologies if I have missed something and it is in an FAQ somewhere, although I have done an initial search. TIA Charles Tolman