I've been waiting for a reply, too;)
What you're asking is extremely difficult. The only way I have ever found to do this reliably is to demux the original(s) and put the whole thing back together as a new DVD, using a DVD authoring tool such as ReelDVD. This takes lots of time and effort and a fair amount of skill. Depending on the value you place on your time, it probably isn't worth it.
You see, if you just delete a title (and some of DVD2One's competitors can do this), but don't make allowance for the fact that it's no longer there by editing the IFO files, then the moment the path of the DVD execution leads to the door of the missing title, the player will hang up. It is this latter task of modifying the IFO files that no one seems to have grappled with successfully, possibly because each DVD is so differently 'arranged'.
It's a bit like the search for the holy grail and for the moment anyway, just as elusive.