I believe you are talking about tsMuxeR. If you have the blu ray movies saved in file format, you can open the main movie m2ts file (found in the Stream folder) with tsMuxeR and select the video, audio and subtitle streams that you want to save, then output as a blu ray video. You will lose the menus this way, and extras.
You'll run into some blu ray movies that split the main movie into several different m2ts files. For those, I'd use ClownBD to get them unified and select the audio and subtitles you want. http://www.videohelp.com/tools/Clown_BD
If you want the menus intact, look at a new tool called ClownBD Copier. Similar to ClownBD. http://www.videohelp.com/tools/Clown_BD_BD_Copier It still seems a bit rough around the edges though, and may not have language selection on the audio streams.