@Cat, Do you mean adding a tet version of a dip plant to your inventory list? Or do you mean having two separate lists, one containing dips and the other tets.
I just looked at your lists. I think you mean adding a sub category to your daylily lists. No, you can't but of course you can create two separate lists for them.
I created a separate Wish lists that includes all types of plants and then separate categories for each type of plant I have. I guess if I was hybridizing with daylilies it would be handy to have the dips and tets in two separate lists.