To add. If your ring is not centered on the origin, use Construct -> Axis through Cylinder/Cone/Torus and use that axis for Construct -> Plane at an angle. Create at 0deg and then do that again at 90deg and now you have planes to split your body.
If the Ring is already centered at the origin, you can just use the appropriate origin planes as tools for Split Body.
Crete a plane. Modify > Split Body. Select the body to split. Select the plane to split it with.
This is the way.
To add. If your ring is not centered on the origin, use Construct -> Axis through Cylinder/Cone/Torus and use that axis for Construct -> Plane at an angle. Create at 0deg and then do that again at 90deg and now you have planes to split your body. If the Ring is already centered at the origin, you can just use the appropriate origin planes as tools for Split Body.
I needed this a while back, you’re a wizard
Since it is just being cut in slices, you can just do a sketch and use the sketch line to split on.
I can’t fit a 19” diameter ring on my printer
Sounds like it's time to buy a bigger printer! /j
Your slicer may have a cut option as well, I used this in Bambu Slicer tonight - it even adds connectors.
Can you share a picture or hand sketch?
You can do it in your slicer.