Using the XOR Weld Tool With Solid Shapes in Version 5
Try this method. Create your inner and outer rings, dimension to your desired interior width, then make path on the two rings.
Use the shape tool to draw a rectangle that looks more like a thin line, and place it so that it dissects the two halves of the ring. Using the XOR weld tool, split this ring into two half rings.
Separate the two half rings, then perform a similar XOR weld to each half.
Ultimately you should be left with four quarter rings. You can still manipulate their characteristics by using node editing to shorten or widen each of them
Position one quarter ring so that it is slightly overlapping the exterior of the primary image. Use the XOR weld tool again to remove area where the quarter ring is placed.
After the tool has completed the task, remove the top portion left over by selecting it, and then using the delete key to remove it.
Be sure to place one quarter ring at a time before utilizing the XOR weld, otherwise you may get an error message, or the weld will not function properly. In this case I added the inner circle last by placing it inside the making a path on the whole object.
Hopefully this will give the tools, or at least spark your own creative thought to make this work for you.