Is there a device that makes my multiple USB powebanks work together? - eviltoast

My current means of powering things is USB rechargable batteries. I have a about five of them that range between small 3000-5000mah ones to a big 20000mah interstate battery jump starter pack. Is there a device that lets me add all their power together into a centeral power source so I don’t have to keep swapping them out?