Deselecting XY Planes


I would like to extract the YZ and XZ planes out of a polysurface and offset them.
Therefore, I would like to remove XY planes from selection.
I was thinking of measuring the vector length of the uv direction or use a boolean toggle for plane normal direction but I am unsure of how to operate it.
Would appreciate some help. Please find attached a screenshot, rhino and gh file.

Thanks in advance.

190714_Deselecting XY Planes.3dm (82.9 KB) 190714_Deselecting XY (6.3 KB)

It’s not clear whether you also want the diagonal plane, so you can use slider to select/deselect.

190714_Deselecting XY (9.4 KB)

Thank you Ethan, very helpful!