I think I know what you are trying to do. A few tips:
Do not use Mp3, they do not work right, use Wav.
If the CDs you are copying have any gaps at all, you will have more work on your hands.
If they have no gaps, then simply copy the CD using Disc At Once burn setting.
If the CD you are copying already has gaps, then you will have to manually remove them in an audio editor if you want a perfect mix.
If the source is Mp3 to begin with (such as a downloaded Mp3 album of an Electronica mix with individual files for each track) you must manually remove gaps (which is not a quick and easy process) Unless there is a new magical program available that can do it for you, which I seriously doubt.
I'm sure someone will tell you to use the "remove silence at the end of audio tracks" setting in Nero, or some other similar setting in a similar program, but I assure you that will not work.
If you have access to the original "gap free" CD just do an exact copy of that disc.
If not, try Sony Soundforge 8 (trial version) or a similar audio editor.
If you like electronica, visit my website: http://www.digitalliquid.tk -->Artists Page-->DJ Mind, there you can hear one of my latest mixes.
Hope I helped...Peace and Luv,