For the custom route, you can contact Whiteflash. Aljdewey's shared prong band sits low to fit beneath her 6 prong, 3 stone e-ring. See her beautiful rings here: https://www.pricescope.com/community/threads/my-custom-rings-from-whiteflash-woo-hoo.16838/
They also have "non custom" shared prong bands. You'd have to check with them on the height to see if one would fit underneath your ring.