We used to but after a bunch of submissions were coming in where you could not tell that any Aiko or Hiro morphs were used, the Admin team made a decision to accept works only using Aiko 3 Hiro 3 and their derivatives like Xin Xin, Melody and Micah, Aiko Toon and Hiro Toon, Bel Bel.
It was just decided there was too much gray area and with other groups that are not so figure specific out there that accept submissions it was easier to limit the submissions here.
Hope this helps