First download and fire up Audacity or some other free sound editing program. Make a dummy sound file of a certain length, say 60-120 seconds. If you want to, make several dummies of different lengths. Then make a playlist of your desired sound files, with the dummy or dummies separating each track. Like:
1. Soundtrack 1
2. [60 sec dummy]
3. Soundtrack 2
4. [30 sec dummy]
5. Soundtrack 3
6. [120 sec dummy]
And so on. Remember to disable the Shuffle feature.
"One of the bitches actually gave birth while she was attacking, and her puppies joined in on the carnage."
--the awesomeness that is Boatmurdered.