Adding relationships to a custom m_iClass?

I’ve been wondering about this one since I started using m_iClass, it seems that the Add_NPC_Class function makes a blank class, having no relationships with any other SNPC m_iClasses… I’ve only used classes made for Half-Life 2, (CLASS_COMBINE,CLASS_ANTLION) and they of course work, but for CLASS_DINOSAUR for instance, no class will attack it and it will attack no other SNPCs/NPCs.