Some websites use the same login for multiple domains (i.e. steampowered.com and steamcommunity.com), however it is not possible to have a single entry for both domains or link those entries so they stay synchronized when you change your password.
I would like to report the opposite idea: where I work I need access with different credentials to the same domain, but in different paths. For example: mywork.com/path_a and mywork.com/path_b So I would like the credentials to be associated not only with the domain but also with the page path. Also I would like the credentials to be associated with a title, so that if I need to use multiple credentials in the same place with the same username but different password I can do so.