Extract a "broken" chapter...

[Nocturne]

Hello, i have a TV serie DVD with the IFO broken, so it say the chapter time is 21 minutes and not 44 minutes (episode 3), but all the video is present in the VOB files, i can extract it after use VOBMerge and encode it singulary with HandBrake and timestamps. But i would love to make a remux with all the episodes... can you help me to extract it in expert mode please?

I have try this syntax: 1:6@3 and it not work...