You can use the Pocket DVD Wizard V4.1 or later to back up more than one chapter from a DVD.

 

Simple select the chapters you would like to back up by holding down the shift,  or ctrl key while making the seelction,  and the Pocket DVD Wizard will automatically convert the chapters for you,  placing each in a separate file.

 

As different chapters may be different lengths,  the target file size will be set according to the size of the memory settings you select for the first track.  The second and subsequent track sizes will be set to the same 'bitrate' as the first to maintain a constant quality.