ZBrushCentral

Closing holes on hollow cylinder

Hi there,
I’m currently making a dice tower that uses a hollow cylinder. I have to slice the tower in prep for 3D printing. My issue is closing the holes after slicing. I need to close the holes between the inner and outer walls. However, close holes or Dynamesh close across the whole cylinder.
Any help greatly appreciated! Thanks
AndrewZBrush_holes