@Jed_Campbell 's solutions could work. You could also do this using Disallowed Combinations in Custom Design. Here is the script for the disallowed combinations for 2 factors, each with 3 levels:
X1 == "L1" & X2 == "L2" | X1 == "L3" & X2 == "L2" | X1 == "L1" & X2 == "L3"
You can specify this with the Disallowed Combinations Filter in Custom Design:
![Phil_Kay_0-1669881069884.png Phil_Kay_0-1669881069884.png](https://community.jmp.com/t5/image/serverpage/image-id/47814i5DCD67C06CB8200A/image-size/medium?v=v2&px=400)
I think that will work but it yields a fairly horrible looking design (attached). I still don't know enough about your experimental objectives to really know, but I have a strong feeling that this way of defining the factors is going to be a problem. I have never seen an example like this. But, again, I don't know enough about what you are trying to achieve.