There are two problems with the big water jug. First, it's gigantic and cumbersome. Second, the water doesn't pour out smoothly; it splashes everywhere and goes "glug glug glug".
user18894's siphon answer is probably easiest, but you can also use a standard water pitcher as an intermediate container. A water pitcher has a big open top, and a spout to make it easy to pour.
- Pour water from the big jug into the pitcher.
- Pour water from the pitcher into your smaller bottles.
It may be useful to use a funnel to pour the water "accurately" from the pitcher through the neck of your water bottles. That will depend on the design of the water pitcher's spout, and the size of the opening of the water bottles.
