Hi Emily –
I can’t quite picture what you have in mind — is there an image in a publication or online that is similar to what you are trying to make?
You might try using a cutting plane in the 3D view. You can turn toggle these using the x/y/z keys. E.g., for press x once to cut in the +x direction, a second time to cut in the -x direction, and a third time to turn off the cutting plane.