Hi
Actually it is remarkably close to the origins of western song, that of "plain song" or "plain chant", the forerunner of Gregorian Chant. It's been a while since I studied the form (almost 20 years) but beginning with only a single voice it evolved to commonly be made up of 4 voices. It was the first notated music. No meter was used. Each vocal part had it's own melody line and timing, length an repeat. The voices would then weave in and through each other creating interesting combinations. Although section lengths are not identical to yours they are similar in notion. Each is cyclic. If I remember correctly, and I may not be exactly accurate, they worked with an elementary rhythm, compound time and composite rhythm.
You may find this document of interest:
http://media.musicasacra.com/pdf/plainsong.pdf
Modern music notation programmes and sequencers are geared to deal with standard note timing, time signatures and tonality. They don't cater for composition and perform any that is anything less than mass market. That being said I haven't looked for a while, but my guess is you will be looking for a highly specialised "off the beaten track" tool.