Select Shared Edge from the Outside Cut Optionsdropdown control to cut the shared edges of the outside cuts on the CMC Z1 and Z (9000z).
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Shared Edge Definition
Select Shared Edge from the Outside Cut Optionsdropdown control to cut the shared edges of the outside cuts on the CMC Z1 and Z (9000z) as one stroke between the designs instead of cutting the outside of each mat individually.
When Tiling, make sure that the Spacing under the Setup Tab is set to zero (0) so that each design shares the outside lines with the next design, so it will only cut the single line between them.
If you have Remnant Trimming on, it will also cut off the scrap edge.