Is there software to combine 2 DVDs onto 1?

I have been using AnyDVD with DVDFab to put a single DVD9 movie on 2 DVD5s so as not to use compression get artifact on large displays. But when I play them on portable DVD players to use with travel, it does not matter because I cannot see the artifact with small screens.

Anyone know of software to take a split movie on 2 DVD RWs and and combine it back together on a single DVD RW?

Thanks in advance.

Dvdshrink in reauthor mode for example.