Place chicken in a large zip-top plastic bag; add 1 cup marinade. Seal bag; toss gently to coat. Place pineapple, bell peppers, and onion in another large zip-top plastic bag; add 1 cup marinade. Seal bag; toss gently to coat. Refrigerate bags 2 hours, turning occasionally.
Drain pineapple mixture, discarding marinade. Place pineapple mixture and tomatoes in a large foil cooking bag. Drain chicken, discarding marinade. Place chicken on top of pineapple mixture. Seal and cut 6 (1/2-inch) slits in top of cooking bag. Place bag on grill. Grill 25 minutes or until chicken is done. Cut bag open with a sharp knife or cooking shears. Carefully peel back foil. Sprinkle with cilantro.