In that case I’d have a sheet for the product, a sheet that lists the product id and the accessory id, and then a sheet to list the accessories. So basically there would be a crosswalk sheet in the middle. In that case I would create a multiple relation from the products sheet to the crosswalk sheet. Then I would create a lookup column to get an array of all related accessory id’s from the accessory id column in the crosswalk sheet. Then I would use that lookup column to create a relation to the accessories sheet. That last relation is what you would use to show a list of accessories in the product details. Of course that method uses many more rows compared simply creating an array column with only 10 accessory options. But we are building a airplane, soooo…