I use this as well. You don't need a site specific addon with this. It's actually useful for separating my different google accounts as well. I'd love an extension that makes all tabs in the a particular container private. That way, any kind of tracking would be opt in by assigning it a non private container and limited to that container.
I'm still waiting for bookmarks with the target container baked in. I also use separate containers for three different Google accounts, but opening a bookmark to a Google drive document or file is annoying, because I always have to open a specific container for that Google account tab first so the document access attempt is from the right account.
