How can I make my own J2Os (fruit juice drink)?

For those of you lot who aren’t British (unluckily :P) or have never heard of them, J2Os are fruit juice drinks made with 50% fruit juice. I quite like them, but they are too expensive to buy on my student budget. I was wondering if there was any way to make them with just fruit (in the same percentages) and a blender or if there was more to making fruit juice drinks than I thought.

Just for reference (and your help) the ingredients of my favourite J2O (orange and passionfruit) is:

Water, Fruit Juices from Concentrate (Orange Juice 35%, Passionfruit Juice 5%), Sugar, Stabiliser (Pectin), Citric Acid, Flavourings, Colour (Anthocyanins), Preservative (Potassium Sorbate), Antioixidant (Ascorbic Acid).

Thanks for the help.