How to create *.idx subtitle files

Question

I am trying to play movies from a USB drive on my DVD player.

I have subtitles for different languages for a movie. (filename.en.srt, filename.fr.srt etc) When I place all the *.srt files in the same directory as the movie file, the DVD player recognises only the first one.

However, if there is only one *.sub file which contains all the language subtitles, and an indexer *.idx file, then the DVD player is able to recognise all the language subtitles.

Can I create an *.idx file manually? Or Is there any software which allows me to create an idx file that indexes multiple *.srt files or combines them?

Solution

Subtitle Workshop can convert convert .srt subtitles to .idx/.sub

Subtitle Workshop is freeware.