How do you merge vob files into a single file while keeping subtitles?

Sorry if this is in the wrong section but I know one of you awesome lovely nerds will know this. I ripped a DVD today on to my PC using DVD Decrypter (first time in over a decade) and it worked just as good as I remember. Only thing is I need the subtitles as it's a foreign language movie and, obviously, I want the entire thing as just one video file and not six. I found a couple of apps I used in the past to merge them all into one and each time it worked great... but the subtitles were gone and I can't figure out what to do. If one of you awesome lovely nerds could tell me or point me to a YouTube vid that easily explains it I would be very appreciative. Cheers.