I can't remember how this works exactly, but you may want to double check:
Leaving the "Ignore can_target" value checked will make the permissions not obey the current group settings- as in, your lower groups that have access to "tp" may now be able to teleport the admins and superadmins. If you leave it unchecked, it should still let them not teleport themselves, but also not teleport those in groups above them (based on your can_target value for the group).