So, I understand the theory behind importing multiple materials at once using the spreadsheet method - all good. What I want to know is how I can get different sheet sizes to associate with the same material using this method. I have all of the materials our supplier has available laid out nicely in a spreadsheet, but I currently the secondary sheet sizes won't import into the microvellum database.

For example, say I'm trying to import 16mm White Melamine and have it available in 2400x1200 and 3600x1800 sheets. How do I import this in the spreadsheet and have both sizes associate with my new material?