Watchlist TV Series

So, if I add a series that has 20 episodes in it....I don't have any way to log that I have seen 3 out of 20. Trakt gives that option, but it is a less official database and that has its own issues. But I would like to check the episodes that I watched. Also, if I have seen all of a series but they have another season greenlit, it stays on my list. So, if I could mark that I have seen 20/20 it can stay on the watchlist, but maybe shoot to the bottom in an "all caught up" greyed out section.