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I think that, if you did the 5 songs in the file simultaneously (and that would sound odd) any hope of separating them is just not there. Of course.)
But, if you performed and recorded them like this:
song1..... song2....... song3... song4............. song5.......
then yes, they can be separated... or, the file can be 'chopped up' into 5 pieces, each with its particular song in it.
But the best thing to do, is to convert the recording to a high-quality WAV file, first. WAV files can be divided easily, you see: they have no header, and they aren't encrypted either.
Does this sound right to you?
If so, what file format is the 5-song file in, currently? (If in several copies in different file formats or file types, what file types are they in total?)