Please help!!

I have a one title dvd video with 2 selectable subtitles. The issue is I want to cut and then re-join some parts of the video to rearrange the order it will be play in the title. Also, I want to be able to retain the option of the selectable subtitles when later I burn the files to a new dvd-r.

I already rip the dvd with DVD Decrypter in IFO mode. I ended with two *.sup files. I know they are the subtitles, but don't know how to edit them in the same way I do with the mpeg-2 file (audio-video multiplexed).

Is anyone out there that can tell me how to do this?