Use MKVtoolnix to combine each part and it’s accompanying subtitle into a MKV file.
Once you have 3 MKV files with embedded subtitles, use this method to concatenate all 3 into one file: [HowTo]: joining multi-part movies files with MKVtoolnix GUI
Use MKVtoolnix to combine each part and it’s accompanying subtitle into a MKV file.
Once you have 3 MKV files with embedded subtitles, use this method to concatenate all 3 into one file: [HowTo]: joining multi-part movies files with MKVtoolnix GUI