There's always room for jello, or in this case, fruit juice gelatin.Bloom 2 packets of gelatin (I use Knox) in 1/2 cup cold water.
Heat 3-4 cups juice to near boiling.
Add bloomed gelatin and 1-2 Tbs lemon juice.
Cool to near room temperature (could put over ice or cool water to speed it along).
Add fruit.
Refrigerate until set.
I use 3 cups of juice for a firm gelatin. More juice would result in a softer set.