<lookupSet>
    <!-- this should only include items which are active - you don't need to pass the whole set, since we already have the full set of items -->
    {foreach from=$aFieldLookups key=iFieldId item=aLookups}
    <field field_id="{$iFieldId}">
      {foreach from=$aLookups item=iLookupId}
        <lookup lookup_id="{$iLookupId}" />
      {/foreach}
    </field>
    {/foreach}
</lookupSet>
