Sweet and Sour Bean Salad

1 can green beans, rinsed and drained
1 can cut yellow wax beans, rinsed and drained
1 can kidney beans, rinsed and drained
1 can butter beans, rinsed and drained
1 large green bell pepper, diced
1 large red onion, sliced and separated into rings
1 (4-ounce) jar pimentos, diced
1/2 cup salad oil
2 cups thinly sliced celery
1 1/2 cups cider vinegar
2 cups sugar
2 teaspoons salt
1/2 teaspoon freshly ground black pepper
1 can tomato soup, undiluted

Place all the beans, green pepper, onion and pimentos in a large mixing bowl. Add the oil and celery. In a saucepan, combine the vinegar, sugar, salt, pepper, and tomato soup. Bring to a boil and pour over the vegetables. Toss the mixture lightly with 2 forks. Do this several times as the mixture cools. Cover the bowl and refrigerate at least 4 hours before serving. The salad will be better if kept chilled 24 hours before serving. Drain and reserve liquid before serving; it will keep for several days. The reserved liquid can be poured over the leftovers. Add more sugar, if desired.