This addon does exactly what I want - links a bookmark to be opened in a specific container. I use it a lot when managing multiple Zazzle stores and their associated Pinterest accounts.
The interface is a little bit clunky - the box to select bookmarks and containers is very small so you always have to scroll it. And it would obviously be easier if there were some kind of easier integration like right clicking on a bookmark and choosing its container that way. But for now this does the job, thank you!