Cut the racks of ribs in half and place them in the slow cooker.Add the onions, garlic, salt, and pepper, then place the lid on the cooker and cook on low for 8 hours, making sure not to lift the lid or otherwise disturb the ribs.Strain off all of the cooking liquid, making sure not to lose any of the garlic or onions. Next, make the sauce. Combine the preserves, ketchup, barbecue sauce, and hot sauce in a medium bowl, and stir it until it’s all combined. Pour the sauce over the ribs, and use tongs to move the ribs around in the sauce as much as you can. Note that the ribs will be falling apart by this stage, so you won’t be able to be too rough with them. Place the lid on the slow cooker and keep the ribs on warm for 20 minutes, or until you need them. Serve ’em on a plate, if they can travel that far without falling to pieces. Succulent and delicious!