When you talk about bootleg copies that have 4-5 movies in each Single layer DVD, they usually dont have any special features and in some cases have a few scenes from the main movie cut in order to fit into one DVD after the compression.
What you can do is use a program like Visual Hub where you can further compress the movies you have and try putting it into iDVD then.. or compress for DVD in Visual Hub itself.. That should easily accomodate your 3 movies into a single DVD..