In file SetItemGrp find: num=value
In file ItemName find: name_class=value
values must match!
Edited: and if you are using same helmet for all three kind of apella sets,leave its value as it is: name_class=-2
you can use these shared npc's for freya if you want,it's not only for interlude,just need make lines for your server in npcgrp file and thats all :) i wrote that it is for IL client,because npcgrp taken from there.