Can someone tell me a feasible way of bottling home made flavoured sparkling water (in pet bottles) without it getting flat?

Put the lid on.

You only lose carbonation every time you open the container.

put the lid on.

You only lose carbonation every time you open the container.

Thanks but that's not quite what I meant... I make the sparkling water in large barrels... around 55 gallons to yield around 300 or so 16 oz pet bottles... I want to know how I could bottle it without the sparkling water in the large container becoming flat during the duration of the bottling process (say around 40 mins)

Hmmm, would a tap system be good enough?