Jelly is the stuff with no fruit in it. It's made exclusively from the juice. Jam has little bits of fruit in it and "preserves" are big chunks of fruit! Just for comparison: Think "grape" generally when you think jelly and "strawberry" generally when you think jam. Those are basically representative when you are thinking of the texture you want.
It sounds like jelly may be what you are looking for.
First step in jelly is to make the juice. If you will look at my avatar, that's a picture of the blackberries I used to make one batch of blackberry jelly. (Exactly that amount. About 2/3 full of a medium size collander.) If I had to guess, I would say maybe two or three quarts of berries.
Put the berries in a big boiler and cover with water. Boil them and mash them a little with potato masher. Then drain them through a wire-mesh strainer into a bowl.
(I think if you wanted jam, you could just strain it through something with bigger holes.)
You need 3.75 cups of juice. You can add up to a couple of ounces of water to make enough if you don't get enough from the fruit.
Put the juice in a big pot and add your pectin. Bring it to a full rolling boil. Add your sugare (4.5 cups). Bring to a boil again stirring constantly. When it comes to a full boil, boil for exactly one minute. Remove from heat.
Pour into sterilized jars. Wipe off your jar rims. Put on the lids & rings. Process in a boiling water bath for five minutes.
Tada! Jelly.
Cassandra
but either way, that recipe on the box won't steer you wrong!
