I'm not sure of the brand configuration, but I assume that the towel bar in question is mounted on something, such as the back of a door (?).
Many of us have used shoe pockets, but I screwed ours directly to the door (did not hang it from a bar). This one is from Container Store and I had to cut off the 4th column of pockets to make it fit. I use it for small linens, maps and other literature, paracords, barf bags, kitchen stuff, etc.
This shows a closet door mount, but if you have a shower curtain in your wet bath, it could be pulled in front of whatever is mounted on the back of that door to keep it from getting wet.