I have a 2x3 design with 6 different groups, all between subject data. I would like to assess an interaction effect between the factors Diet (2 groups) and Genotype (3 groups). The lefse setup shows the option class and sub-class, which suggests a within subject design for the sub-class. Is this indeed the case? This is not in accordance with my study design. Is it possible to test for between subjects interaction effects in lefse?