don't combine them

last time I can't find an example,
actually, I don't suggest combine these two.
I II< III<
I> II< III<
1. because if there's one day you see I< II< III<, then you don't know I II< III< should belongs to which one.
2. actually, I II<> II> which might be combine with I> III II and I> III> II and I> III> II<, but you'll see I II<> III> II< as different one.