So your kids like Trix yogurt so it doesn't work for you to make yogurt. Weeeelllll let me tell ya, I have a recipe for a Trix like custard yogurt you can make cheap and the kiddies will love!
Trix style custard yogurt
1 pkg flavored Jello (or the generic equivalent)
1 cup water
3 cups plain yogurt
1/3 cup sugar
Boil your water and add the Jello, and sugar. Mix well. Fold in the yogurt until well incorporated and smooth. Chill to set.
TIP: If you don't want to use the Jello, you can use 1 cup juice concentrate (like grape or juicy juice) and a pkg of unflavored gelatin instead of the Jello and water.