You could just turn off AutoDJ when you want the music to stop. Personally I don't see any reason to generate a play queue that you don't intend to actually play.

Firstly, I have no idea what you mean by "Advanced Playlists", but that wasn't quite what I was suggesting. I never make playlists.
I always run MediaMonkey with AutoDJ selecting random tracks from a very large library. When I want to hear a complete album, I use play next, or play last to insert it into the on-running random playlist, so that as soon as the album is finished, it goes back to random track play. All I want, is to be able to select a particular track in the automatically generated playlist & get play to stop after that one. It's a way of setting MM to stop after an approximate time, without having to wait until the track I want to stop after is already playing.

Already in the advanced playlists with the rules add xxxxxxnumber of songs.

It's a little thing, but there's something that has been on my personal wishlist for a long time...

The Play menu has a "Stop After Current" link, which is useful, but...

I would really love to be able to right-click any track currently in the playlist & select "Stop After This Track".
A useful addition to the Playlist menu would be one for "Load No More Tracks For This Session", which would have a similar usage.