Wash tomatoes, apples and peppers thoroughly. Trim and quarter tomatoes. Core and quarter apples. Seed and slice peppers. Peel and quarter onions.
Put vegetables and fruit through the coarse blade of a food grinder or process in small batches in a food processor. As each batch of fruit-vegetable mixture is processed into medium chunks, place it in a large Dutch oven or roasting pan. Add all remaining ingredients to the pot and stir with a wooden spoon to blend thoroughly.
Bring mixture to slow boil over medium heat, then simmer, uncovered, stirring frequently to prevent scorching, for 30 minutes. Remove from heat. Immediately pour relish into 6 sterilized pint jars. Fill to within 1/2 inch of the top and seal at once. Cool before storing.