I'm hiding various pages in a very long packing list report by applying an if before the pbr. This is working well except where I've got it showing or hiding a serial number page based on

<#list record.item as item><#if item.custcol_invdetail?has_content>
<pbr />

I'm obviously getting duplicate pages where more than one line item is serialised. Can anyone think of a better method that will show a page for orders that contain serialised inventory without duplicating? Break might be the way to do it. Just need to find the correct way to apply it.