Fruit nectars rather than juices are better and tomato derived juices are thicker as well. There are a couple of commercially available thickener available and I'm sure someone else can give you the names.
Hi Tracy maybe this will help. today i ordered from a company on e-bay called independance at home. i don't know if they will have it (cheaper prices) but i know this company does. www.sammonspreston.com. i haven't tried the thickeners but. its worth a try. just type in E1262-01 or food thickener. hope this helps.:-D janf