batch subtitle control?

Hi all -

I know that in DVD SP it is not possible to move multiple subtitles at one time, but is there any way to do this in general?

I want to subtitle a project for which the opening titles are not finished, so I don't know the exact timecode location for the subtitles in terms of the entire project. I do, however, know where the subtitles should go relative to each other and the individual scenes in the movie, so I'd like to set them up and then be able to move them, all together, a few seconds in either direction, as opposed to moving each individual subtitle or re-entering timecodes for each subtitle on a spreadsheet / text file. Is that possible, or do I need to wait until the movie, with titles, is absolutely locked?

thanks
Rich